Methodology and data status

Every calculator on this site runs the same open sequence of rules against a dated set of parameters. This page lists both.

Calculation sequence

Net profit = self-employment income − business expenses (Schedule C). A loss is reported on the page but treated as zero profit for the rest of the sequence: the calculator does not offset a Schedule C loss against wages or other income, does not apply the excess business loss limit of §461(l), and does not carry a net operating loss to another year.
Self-employment tax (Schedule SE): net profit × 0.9235 = net earnings. Social Security at 12.4% on net earnings up to the wage base, less your own W-2 wages already subject to Social Security (the base is per person, so a spouse's wages do not use it up); Medicare at 2.9% on all net earnings; Additional Medicare Tax at 0.9% on wages (both spouses' on a joint return) plus net earnings above the filing-status threshold (Form 8959). Nothing is owed below $400 of net earnings.
Adjusted gross income = net profit + W-2 wages (yours and, on a joint return, your spouse's) − half of self-employment tax − retirement plan contribution (capped at what the chosen plan allows: a SEP-IRA's 20% of net earnings, or a solo 401(k)'s deferral — less deferrals made at a job — plus 20%, under the §415(c) limit, with the age catch-up on top; never more than net earnings) − self-employed health insurance premiums (capped at net earnings less the retirement deduction) (Schedule 1).
Qualified business income deduction (§199A): 20% of qualified business income (net profit minus the deductible half of SE tax, the retirement deduction and the health insurance deduction, per Reg. §1.199A-3(b)(1)(vi)). Above the taxable-income threshold that amount is reduced linearly over the phase-in range, on the assumption of a sole proprietor with no W-2 employees and no qualified property (§199A(b)(3)(B), Form 8995-A Part III); the result is then capped at 20% of taxable income before the deduction (§199A(a)(2), Part IV). The reduction comes before the cap, not after it. The curve is the one for a business that is not a specified service trade or business (health, law, accounting, actuarial science, performing arts, consulting, athletics, financial and brokerage services, or one whose principal asset is its owner's reputation or skill — §199A(d)(2)); a specified service business inside the range loses the deduction faster and above it entirely, and a business with W-2 employees or qualified property may keep more, neither of which the calculator models.
Taxable income = AGI − standard deduction − QBI deduction. Itemized deductions are not modeled.
Federal income tax from the bracket schedule for the filing status.
Child tax credit (§24): per-child and per-other-dependent amounts, reduced by $50 per $1,000 (or part) of AGI over the threshold; the nonrefundable part offsets income tax, and the refundable part (Schedule 8812) is limited per child and by 15% of earned income over $2,500.
Earned income credit (§32): for filers with qualifying children, the credit rate times earned income up to the maximum for that number of children, reduced at the phase-out rate on the greater of AGI or earned income above the threshold (joint filers use the higher threshold); fully refundable. Computed by formula rather than the IRS lookup table, so it can differ from the table by a few dollars. Qualifying children are the children under 17 plus any entered as 17 to 23 and qualifying (under 19, or a full-time student under 24, or permanently and totally disabled — §32(c)(3)); the latter count for the $500 credit for other dependents, not the child tax credit. Married-filing-separately filers and filers with investment income above the limit get none. The smaller credit for filers without children requires the filer to be 25 to 64 — on a joint return, at least one spouse (IRS, "Who qualifies for the EITC") — which the calculator cannot know, so it is included only when the "no children and aged 25–64" box is ticked.
State income tax by state model, described below.
Amount to set aside: federal tax less any federal withholding entered, plus state tax less any state withholding, each floored at zero (a federal refund cannot pay state tax). The federal balance is shown in four equal Form 1040-ES installments; the state balance follows the split declared in the state's data file — four equal installments everywhere except California, whose Form 540-ES schedule is 30% / 40% / 0% / 30%. The quarterly calculator applies the §6654 safe harbor (the lesser of 90% of this year's tax and 100% or 110% of last year's), credits withholding one quarter per due date (§6654(g)) and each estimated payment on its date, reports which past installments were met, sets the next payment to catch up any shortfall (payments go to the oldest unpaid installment first, §6654(b)(3)), and estimates the penalty accrued so far at the published §6621 rates.

The 1099 vs W-2 calculator runs the same sequence twice — once with the pay as wages, once as self-employment income with the entered expenses, premiums and retirement contribution — adds the employee share of Social Security and Medicare (6.2% up to the wage base plus 1.45%) on the wage side, counts employer-paid benefits and match as money kept, and solves by bisection for the contract pay at which the two "kept after tax" figures are equal.

State models

No income tax (Alaska, Florida, New Hampshire, Nevada, South Dakota, Tennessee, Texas, Washington, Wyoming): state tax is zero. State-level business taxes that may still apply are described on each page but not calculated.

Bracket states: a single model driven by one data file per state and year. The file declares the bracket schedule, standard deduction, personal and dependent exemptions (as deductions or credits, flat or stepped by income), whether the state conforms to federal AGI (and therefore allows the half-SE-tax deduction), and any business-income deduction with a separate flat rate on the excess. Local income taxes are never calculated.

California: its own module, because of the Mental Health Services Tax and exemption credits.

Not modeled

Itemized deductions. (The self-employed health insurance deduction and SEP-IRA / solo 401(k) contributions are modeled from 2026-09-08: the health insurance deduction is capped at net earnings less the retirement deduction (§162(l)(2)(A)); the retirement deduction is capped by plan type, following Publication 560's Deduction Worksheet for Self-Employed: the elective deferral first, then the employer contribution at no more than half of what is left (§415(c)(1)(B) measures annual additions against compensation, which for a self-employed person is net earnings after the employer contribution with deferrals added back), then the §414(v) catch-up. The calculator asks the plan type, the age band and any deferrals or catch-up made at a job; an entry above the cap is reduced to it with a note. Ceilings are floored to the cent, because a maximum must never round up. Two limits are assumed rather than asked: the contribution is treated as entirely pre-tax, so designated Roth contributions would count against the same ceiling without being deductible; and the worksheet's own inputs are whole dollars where this engine keeps cents, so a hand-worked Form 1040 can differ by a dollar or two. Both reduce AGI and qualified business income; neither changes self-employment tax. Eligibility for either deduction is not tested.)
S-corporation or partnership elections; income from more than one business; net operating losses and the §461(l) excess business loss limit.
A spouse's own self-employment income: the calculator carries one Schedule SE. A spouse's W-2 wages are modeled (from 2026-09-18).
Credits other than the child tax credit and the earned income credit: education credits, the child and dependent care credit, the premium tax credit. State earned income credits that are a share of the federal credit, and per-child state credits keyed to the federal definition of a qualifying child, are modeled where the state's data file declares them; state credits that depend on a child's exact age or on inputs the calculator does not collect are listed on each state's page instead.
City, county and school-district income taxes.
Phase-outs of state exemptions at high income where noted in a state's data file.

Most of these would lower the tax owed, so the estimate usually runs high; city, county and school-district taxes, and the loss rules, run the other way. Check the notes on your state's page.

Worked examples

Eight cases computed at build time by the same engine and data files the calculators use, so they always match what the calculator shows. Each opens in the calculator with its inputs filled in; the figures can be reproduced by hand from the sequence above and the 2026 parameters in the data files.

Texas, single, $80,000 of 1099 income, $8,000 of expenses

The site's default case: self-employment tax, the ½-SE-tax adjustment and the QBI deduction with no state tax. Open in the calculator.

Net profit	$72,000
Self-employment tax (Schedule SE)	$10,173
Adjusted gross income	$66,913
Standard deduction	−$16,100
Qualified business income deduction	−$10,163
Federal taxable income	$40,651
Federal income tax before credits	$4,630
Federal total (income tax after credits + SE tax − refundable credits)	$14,803
Texas income tax	None
Total federal + Texas	$14,803
Set aside per quarter	$3,701

California, single, $120,000 of income, $20,000 of expenses

A state with its own brackets and exemption credits; the 2025 version of this case is pinned in the engine's tests. Open in the calculator.

Net profit	$100,000
Self-employment tax (Schedule SE)	$14,130
Adjusted gross income	$92,935
Standard deduction	−$16,100
Qualified business income deduction	−$15,367
Federal taxable income	$61,468
Federal income tax before credits	$8,235
Federal total (income tax after credits + SE tax − refundable credits)	$22,365
California income tax	$4,398
Total federal + California	$26,763
Average per quarter	$6,691

North Carolina, head of household, $45,000 of income, $5,000 of expenses, two children

Low enough income for the refundable child tax credit and the earned income credit to matter; North Carolina's child deduction applies. Open in the calculator.

Net profit	$40,000
Self-employment tax (Schedule SE)	$5,652
Adjusted gross income	$37,174
Standard deduction	−$24,150
Qualified business income deduction	−$2,605
Federal taxable income	$10,419
Federal income tax before credits	$1,042
Child tax credit and credit for other dependents (nonrefundable + refundable)	−$4,400
Earned income credit	−$4,518
Federal total (income tax after credits + SE tax − refundable credits)	-$2,225
North Carolina income tax	$521
Total federal + North Carolina (a net refund)	-$1,704
Set aside per quarter	$130

New York, married filing jointly, $150,000 of income, $30,000 of expenses, plus $60,000 of W-2 wages with tax withheld

Wages use up part of the Social Security wage base, and federal ($7,000) and New York ($3,000) withholding reduce what is left to set aside. Open in the calculator.

Net profit	$120,000
Self-employment tax (Schedule SE)	$16,955
Of which Social Security, on the filer's own base	$13,741
Adjusted gross income	$171,522
Standard deduction	−$32,200
Qualified business income deduction	−$22,304
Federal taxable income	$117,018
Federal income tax before credits	$15,168
Federal total (income tax after credits + SE tax − refundable credits)	$32,123
New York income tax	$8,396
Withheld from W-2 wages (federal + state)	−$10,000
Total federal + New York	$40,519
Left to cover with estimated payments	$30,519
Set aside per quarter	$7,630

Ohio, single, $60,000 of income, $10,000 of expenses

Ohio's business income deduction removes the first $250,000 of net profit from the state's brackets, so the state tax is zero. Open in the calculator.

Net profit	$50,000
Self-employment tax (Schedule SE)	$7,065
Adjusted gross income	$46,468
Standard deduction	−$16,100
Qualified business income deduction	−$6,074
Federal taxable income	$24,294
Federal income tax before credits	$2,667
Federal total (income tax after credits + SE tax − refundable credits)	$9,732
Ohio income tax	$0
Total federal + Ohio	$9,732
Set aside per quarter	$2,433

Texas, married filing jointly, $100,000 of 1099 income, plus a spouse's $200,000 of W-2 wages

The spouse's wages are taxed, lift the couple over the $250,000 Additional Medicare Tax threshold and count in AGI, but they do not use up the filer's own Social Security wage base, which is per person: the full 12.4% is still due on the profit. The same $200,000 entered as the filer's own wages would remove that Social Security tax. Open in the calculator.

Net profit	$100,000
Spouse's W-2 wages (joint return)	$200,000
Self-employment tax (Schedule SE)	$14,130
Of which Social Security, on the filer's own base	$11,452
Additional Medicare Tax (Form 8959, both parts)	$381
Adjusted gross income	$292,935
Standard deduction	−$32,200
Qualified business income deduction	−$18,587
Federal taxable income	$242,148
Federal income tax before credits	$43,312
Federal total (income tax after credits + SE tax − refundable credits)	$57,822
Texas income tax	None
Total federal + Texas	$57,822
Set aside per quarter	$14,456

North Carolina, head of household, $45,000 of income, $5,000 of expenses, one child under 17 and an 18-year-old who qualifies for the earned income credit

The 18-year-old counts for the earned income credit and for the $500 credit for other dependents, not for the child tax credit, so the earned income credit equals the two-child case above while the child credit is $2,200 lower and the other-dependent credit $500 higher. Open in the calculator.

Net profit	$40,000
Self-employment tax (Schedule SE)	$5,652
Adjusted gross income	$37,174
Standard deduction	−$24,150
Qualified business income deduction	−$2,605
Federal taxable income	$10,419
Federal income tax before credits	$1,042
Child tax credit and credit for other dependents (nonrefundable + refundable)	−$2,700
Earned income credit	−$4,518
Federal total (income tax after credits + SE tax − refundable credits)	-$525
North Carolina income tax	$620
Total federal + North Carolina	$96
Set aside per quarter	$155

New Jersey, single, $100,000 of income, $10,000 of health insurance premiums and $15,000 into a solo 401(k)

Which plan the contribution goes into is part of the input, not a detail. Federally the two plans deduct the same $15,000, so the federal figures do not move. New Jersey takes a self-employed 401(k) contribution off net profit and gives a SEP-IRA nothing, so the same dollars in a SEP leave the state tax $947 higher; it takes the health insurance premiums either way, after gross income. Until 2026-09-17 one switch refused all three for New Jersey. Open in the calculator.

Net profit	$100,000
Self-employment tax (Schedule SE)	$14,130
Retirement plan deduction (solo 401(k))	−$15,000
Self-employed health insurance deduction	−$10,000
Adjusted gross income	$67,935
Standard deduction	−$16,100
Qualified business income deduction	−$10,367
Federal taxable income	$41,468
Federal income tax before credits	$4,728
Federal total (income tax after credits + SE tax − refundable credits)	$18,858
New Jersey income tax	$2,596
New Jersey income tax if the same $15,000 goes into a SEP-IRA instead (shown here)	$3,543
Total federal + New Jersey	$21,454
Set aside per quarter	$5,363

Data files and verification status

Every parameter set carries a status; document names below link to the official copy where one is online. draft means the figures were entered from the cited publication but have not yet been re-checked line by line against it; verified means that on the date shown, two independent reads of the primary documents (the revenue procedure, form instructions, or statute — never a third-party summary) produced the same figures, and every difference from the draft was corrected and logged in the file's notes. The verifier is not a licensed tax professional; the check is documentary, and the documents are cited so you can repeat it. Pages for states whose data is still draft are marked as such and kept out of search indexes.

Data set	Status	Last verified	Sources
US federal 2025	verified	2026-09-05	IRS Rev. Proc. 2024-40 (original 2025 inflation adjustments) Public Law 119-21 (One Big Beautiful Bill Act) : raised 2025 standard deduction, made QBI permanent, set CTC to $2,200 SSA 2025 COLA fact sheet : Social Security wage base IRS Form 1040-ES (2025) : estimated tax due dates IRS Rev. Proc. 2024-40 §2.06 : earned income credit amounts and §32(i) investment income limit IRC §6654(d)(1)(B)–(C), (e)(1) and (f) (required annual payment : lesser of 90% of the current year's tax or 100% of the prior year's, 110% when prior-year AGI exceeds $150,000 / $75,000 MFS; no penalty when the tax less withholding is under $1,000; 'tax' = income tax + SE tax less credits other than withholding), read at law.cornell.edu; Form 1040-ES instructions, 'Who Must Pay Estimated Tax' and the Estimated Tax Worksheet IRS Notice 2024-80 (2025 dollar limitations : §415(c)(1)(A) $70,000; §402(g)(1) $23,500; §414(v)(2)(B)(i) catch-up $7,500; §414(v)(2)(E)(i) age 60–63 catch-up $11,250) and the IRS 'COLA increases for dollar limitations on benefits and contributions' table 26 U.S.C. §162(l) (self-employed health insurance deduction : limited to earned income from the business; no deduction for months of eligibility for a subsidized employer plan) and Treas. Reg. §1.199A-3(b)(1)(vi) (the ½-SE-tax, health insurance and retirement deductions reduce qualified business income) IRC §6654(d)(2) and Form 2210 (2025) Schedule AI : annualization amounts 4 / 2.4 / 1.5 / 1, applicable percentages 22.5% / 45% / 67.5% / 90%, the annualized installment capped at 25% of the required annual payment plus any unused room from earlier columns (lines 24–27), self-employment tax annualized with the prorated Social Security limit (Part II) IRS 'Standard mileage rates' page : business rate 70 cents per mile for 2025 (IR-2024-312); Rev. Proc. 2013-13 §4.01: home office safe harbor of $5 per square foot up to 300 square feet IRS 'Quarterly interest rates' page (read 2026-09-08) : §6621 underpayment rate by quarter for 2025: 7%, 7%, 7%, 7%; later quarters are not yet published and the engine carries the last published rate forward, flagged as assumed IRS Publication 560, Retirement Plans for Small Business : 'Rate Table for Self-Employed' (25% plan rate = 0.200000 of net earnings) and the 'Deduction Worksheet for Self-Employed', steps 3–19: the elective deferral first, then the employer contribution capped at one-half of net earnings less the deferral (§415(c)(1)(B) with §401(c)(2)(A)(v) and the §415(c)(3)(D) deferral add-back), then the §414(v) catch-up capped at compensation less other deferrals; §401(a)(17) compensation limit $350,000 for 2025 IRS Form 1040-ES, 'Who Must Pay Estimated Tax : General Rule': estimated tax is required only when the filer expects to owe at least $1,000 after withholding and refundable credits AND expects those to fall short of the 90% / 100% safe harbour Verification: Two independent primary-source checks on 2026-09-05 (Rev. Proc. 2024-40 §3.01/§2.05/§2.27, Rev. Proc. 2025-32 §3–4, Form 1040-ES 2025/2026 rate schedules and SE worksheet, Form 8959 and Schedule 8812 instructions, P.L. 119-21 §§70102/70104/70105, SSA contribution and benefit base table); the two checks agreed on every figure. Notes EITC parameters (2025): earned income amount, maximum credit and phase-out points read from the revenue procedure table; credit and phase-out rates are statutory (§32(b)(1)). The credit is computed by formula, not by the Form 1040 lookup table, so results can differ from the table by up to about $8. The childless credit is only computed when the caller asserts the 25–64 age rule is met. 2026-09-05 audit: HoH 32% bracket ceiling corrected from 250,525 (single figure) to 250,500 per Rev. Proc. 2024-40 Table 2. HoH upper brackets are indexed separately from single and must never be copied from it. Standard deduction reflects the OBBBA-amended 2025 amounts, not the original Rev. Proc. 2024-40 figures. Additional Medicare tax thresholds and CTC phase-out thresholds are statutory and not inflation-indexed. 2026-09-07: estimated-tax safe-harbor parameters added (§6654; unchanged for years) for the quarterly-payment calculator. Two reads: the statute text and the Form 1040-ES instructions. The $150,000 / $75,000 AGI thresholds are not indexed. 2026-09-08: retirement-plan limits added for the SEP-IRA / solo 401(k) input (two documents: the IRS notice and the IRS limits page for the year). The self-employed health insurance and retirement deductions reduce AGI and qualified business income but not self-employment tax or the earned income used for the child and earned income credits; the health insurance deduction is capped at net earnings less the retirement deduction (§162(l)(2)(A)); the retirement deduction is capped at the lesser of the §415(c) limit and net earnings after ½ SE tax — the calculator does not know the filer's age or plan type, so catch-up limits and the SEP-only 20% cap are described on the page rather than enforced. 2026-09-08: annualized-installment parameters (statutory percentages, form factors), the standard mileage rate and the home office safe harbor added for the guides; the mileage and safe-harbor rates are described on the guide pages and are not inputs to the calculators. 2026-09-08 correction: the retirement-plan deduction had been capped only at the lesser of the §415(c) limit and net earnings, so an entry above a plan's real ceiling was accepted (an external review entered $100,000 on $72,000 of profit and got a $66,913 deduction). The calculator now distinguishes SEP-IRA and solo 401(k), applies the 20% self-employed rate, the §402(g) deferral less deferrals made in another employer's plan, the §415(c) cap and the age-based catch-ups, and reduces an excess entry to the plan-specific maximum with a note. Earlier text in this file saying age and plan type were not collected no longer applies. 2026-09-08 correction: the quarterly calculator had taken one 'paid so far' figure, which could not show whether past installments were met and treated withholding and estimated payments alike; the §6654(e)(1) $1,000 test also subtracted estimated payments, which the statute does not. It now credits withholding one quarter per due date (§6654(g)), each estimated payment on its date to the oldest unpaid installment (§6654(b)(3)), reports each installment's status, and estimates the penalty accrued at the §6621 rates; the $1,000 test uses withholding only. 2026-09-09 correction: the solo 401(k) maximum ignored the §415(c)(1)(B) 100%-of-compensation limit, which for a self-employed person makes each dollar of employer contribution cost two dollars of headroom (compensation is net earnings less the employer contribution, with elective deferrals added back). Between about $26,400 and $43,900 of net profit the old figure was too high — at about $32,300 of profit it allowed about $30,000 where Pub. 560's worksheet allows about $27,250 (2026 limits; the exact figures depend on the self-employment tax). The engine now follows the worksheet: deferral, then employer ≤ (net earnings − deferral) ÷ 2, then catch-up ≤ compensation − deferrals; the ceiling is reported as three components that add to the total. Two independent primary-source reads (Pub. 560 worksheet steps 11–13 and the §415/§404/§414 text) agreed on the rule. §401(a)(17) compensation limit added for the employer 25%-of-capped-compensation ceiling. 2026-09-09 (red team): two further corrections to the same worksheet. Each component is now settled to the cent as it is computed, so the catch-up sees the cent released by flooring the employer contribution (at $40,000 of profit with a catch-up it is $6,337.05, not $6,337.04) and the three parts add to the total exactly. And catch-up contributions made in another employer's plan now reduce what is left here: the §414(v) amount is one per individual across employers (Treas. Reg. §1.402(g)-2). An adversarial pass recomputed all 79 combinations of profit, age band and prior deferrals by hand from the worksheet; the remaining differences from a hand-worked Form 1040 are that the worksheet's inputs are whole dollars where this engine keeps cents, and that the ceiling assumes an entirely pre-tax contribution (designated Roth amounts count against it without being deductible). Both are stated on the methodology page. 2026-09-09 correction: the underpayment-penalty estimate was reported even where the statute removes the addition to tax outright — §6654(e)(1) (tax under $1,000 after withholding) and §6654(e)(2) (a full twelve-month prior year with no tax). It is now omitted in both cases, so a page can no longer show an accrued penalty and the reason it cannot arise at the same time. 2026-09-09 correction: the $1,000 floor was treated as a defence against the penalty only, so a filer expecting to owe less than that after withholding was still shown a required annual payment, installments marked short and advice to catch up — while being told no penalty could arise. Form 1040-ES's General Rule makes it a condition of the requirement itself ('you must pay estimated tax if BOTH of the following apply: 1. you expect to owe at least $1,000 after subtracting your withholding and refundable credits'), so the requirement and the whole schedule are now zero, as they already were for the §6654(e)(2) prior-year exception. Estimated payments already made do not count towards the test; only withholding and refundable credits do. 2026-09-17 correction: the §199A deduction applied the 20%-of-taxable-income cap before the phase-in reduction (20% × min(QBI, taxable income) × phase factor) instead of after it (min(20% × QBI × phase factor, 20% × taxable income)), the order §199A(a)(2) and (b)(3)(B) prescribe and Form 8995-A works in Parts III and IV. Every sole proprietor with no other income whose taxable income fell inside the phase-in range was shown too small a deduction and too much tax: for a single filer with $250,000 of profit and nothing else, $24,036.25 became $25,757.15 and the income tax fell by $413.02. The engine test that pinned the old order was corrected, and a line-by-line Form 8995-A implementation now checks 17 hand-worked cases and a grid across both years and all four statuses. The methodology page described the wrong order in the same words and was rewritten. Found by an external review on 2026-09-17. 2026-09-17 correction: the Additional Medicare Tax on W-2 wages above the filing-status threshold (Form 8959 Part I, 0.9%) was left out of the federal total; only the part on net earnings from self-employment (Part II) was counted, although the methodology page said both were. A single filer with $300,000 of wages and no profit was shown $0 of Additional Medicare Tax instead of $900; with $100,000 of profit as well, $831.15 instead of $1,731.15. The 1099 vs W-2 comparison understated the W-2 side's payroll tax by the same amount. The engine now returns the wage part separately, the federal total and the comparison include it, and the breakdown shows it as its own line (the employer withholds it, so a filer who enters the tax withheld from wages already has it covered). Found by an external review on 2026-09-17. 2026-09-17 correction: the estimated tax underpayment charge kept accruing past the return's due date. §6654(b)(2) runs each underpayment from its installment date to the earlier of the date paid and the 15th day of the fourth month after the year ends, so for a 2026 underpayment nothing accrues after 15 April 2027; the engine used today's date without that ceiling, and a link dated later showed a larger figure ($744.26 on 15 May 2027 against $661.41 on 15 April, on $16,000 of unpaid tax). The charge now stops on that day, the per-day figure is zero from then, and the quarterly and penalty pages say that interest and the late-payment penalty on the unpaid tax take over, which they do not estimate. Found by an external review on 2026-09-17.
US federal 2026	verified	2026-09-05	IRS Rev. Proc. 2025-32 (2026 inflation adjustments, incorporating OBBBA changes) SSA 2026 COLA fact sheet : Social Security wage base 26 U.S.C. §199A as amended by Public Law 119-21 : QBI phase-in range widened to $75,000 / $150,000 26 U.S.C. §24 as amended by Public Law 119-21 : CTC $2,200, indexed from 2026 IRS Form 1040-ES (2026) : estimated tax due dates IRS Rev. Proc. 2025-32 §4.06 : earned income credit amounts and §32(i) investment income limit IRC §6654(d)(1)(B)–(C), (e)(1) and (f) (required annual payment : lesser of 90% of the current year's tax or 100% of the prior year's, 110% when prior-year AGI exceeds $150,000 / $75,000 MFS; no penalty when the tax less withholding is under $1,000; 'tax' = income tax + SE tax less credits other than withholding), read at law.cornell.edu; Form 1040-ES instructions, 'Who Must Pay Estimated Tax' and the Estimated Tax Worksheet IRS Notice 2025-67 (2026 dollar limitations : §415(c)(1)(A) $72,000; §402(g)(1) $24,500; §414(v)(2)(B)(i) catch-up $8,000; §414(v)(2)(E)(i) age 60–63 catch-up $11,250) and the IRS 'Retirement topics — 401(k) and profit-sharing plan contribution limits' and 'SEP contribution limits' pages 26 U.S.C. §162(l) (self-employed health insurance deduction : limited to earned income from the business; no deduction for months of eligibility for a subsidized employer plan) and Treas. Reg. §1.199A-3(b)(1)(vi) (the ½-SE-tax, health insurance and retirement deductions reduce qualified business income) IRC §6654(d)(2) and Form 2210 (2025) Schedule AI : annualization amounts 4 / 2.4 / 1.5 / 1, applicable percentages 22.5% / 45% / 67.5% / 90%, the annualized installment capped at 25% of the required annual payment plus any unused room from earlier columns (lines 24–27), self-employment tax annualized with the prorated Social Security limit (Part II) IRS 'Standard mileage rates' page : business rate 72.5 cents per mile for January–June 2026 (IR-2025-128) and 76 cents for July–December 2026 (IR-2026-29); Rev. Proc. 2013-13 §4.01: home office safe harbor of $5 per square foot up to 300 square feet IRS 'Quarterly interest rates' page (read 2026-09-08) : §6621 underpayment rate by quarter for 2026: 7%, 6%, 7%, 7%; later quarters are not yet published and the engine carries the last published rate forward, flagged as assumed IRS Publication 560, Retirement Plans for Small Business : 'Rate Table for Self-Employed' (25% plan rate = 0.200000 of net earnings) and the 'Deduction Worksheet for Self-Employed', steps 3–19: the elective deferral first, then the employer contribution capped at one-half of net earnings less the deferral (§415(c)(1)(B) with §401(c)(2)(A)(v) and the §415(c)(3)(D) deferral add-back), then the §414(v) catch-up capped at compensation less other deferrals; §401(a)(17) compensation limit $360,000 for 2026 IRS Form 1040-ES, 'Who Must Pay Estimated Tax : General Rule': estimated tax is required only when the filer expects to owe at least $1,000 after withholding and refundable credits AND expects those to fall short of the 90% / 100% safe harbour Rev. Proc. 2025-32 §4.14(3) (additional standard deduction under §63(f) for the aged or the blind, 2026 : $1,650, or $2,050 if unmarried and not a surviving spouse) with IRC §63(c)(3) and (f)(1)–(3) (one amount per qualifying condition per person) Public Law 119-21 §70103, adding IRC §151(d)(5) : $6,000 deduction for each qualified individual aged 65 or over for taxable years beginning before January 1, 2029 (2025–2028), reduced by 6 percent of modified adjusted gross income over $75,000 ($150,000 on a joint return), joint return required for married individuals and a valid SSN for each qualified individual; allowed whether or not the taxpayer itemizes, as a §151 deduction from AGI (§63(b)(2) subtracts it for non-itemizers and §63(d)(2) keeps it out of itemized deductions) Verification: Two independent primary-source checks on 2026-09-05 (Rev. Proc. 2024-40 §3.01/§2.05/§2.27, Rev. Proc. 2025-32 §3–4, Form 1040-ES 2025/2026 rate schedules and SE worksheet, Form 8959 and Schedule 8812 instructions, P.L. 119-21 §§70102/70104/70105, SSA contribution and benefit base table); the two checks agreed on every figure. Notes EITC parameters (2026): earned income amount, maximum credit and phase-out points read from the revenue procedure table; credit and phase-out rates are statutory (§32(b)(1)). The credit is computed by formula, not by the Form 1040 lookup table, so results can differ from the table by up to about $8. The childless credit is only computed when the caller asserts the 25–64 age rule is met. 2026-09-05 audit: HoH 24%/32% ceilings corrected to 201,750/256,200 (Rev. Proc. 2025-32 Table 2); QBI MFS threshold corrected to 201,775 (§4.26 lists MFS separately from all other returns); ACTC limit corrected from 1,800 to 1,700 (§4.05(2) — the indexed $1,400 base did not reach the next $100 step). CTC $2,200 and ACTC $1,700 are inflation-indexed from 2026 with round-down to $100; both stayed flat for 2026 (Rev. Proc. 2025-32 §4.05). §199A(i) (added by P.L. 119-21 §70105) guarantees a $400 deduction from 2026 for taxpayers with at least $1,000 of QBI from a business in which they materially participate; the calculator assumes material participation. Additional Medicare tax thresholds and CTC phase-out thresholds are statutory and not inflation-indexed. 2026-09-07: estimated-tax safe-harbor parameters added (§6654; unchanged for years) for the quarterly-payment calculator. Two reads: the statute text and the Form 1040-ES instructions. The $150,000 / $75,000 AGI thresholds are not indexed. 2026-09-08: retirement-plan limits added for the SEP-IRA / solo 401(k) input (two documents: the IRS notice and the IRS limits page for the year). The self-employed health insurance and retirement deductions reduce AGI and qualified business income but not self-employment tax or the earned income used for the child and earned income credits; the health insurance deduction is capped at net earnings less the retirement deduction (§162(l)(2)(A)); the retirement deduction is capped at the lesser of the §415(c) limit and net earnings after ½ SE tax — the calculator does not know the filer's age or plan type, so catch-up limits and the SEP-only 20% cap are described on the page rather than enforced. 2026-09-08: annualized-installment parameters (statutory percentages, form factors), the standard mileage rate and the home office safe harbor added for the guides; the mileage and safe-harbor rates are described on the guide pages and are not inputs to the calculators. 2026-09-08 correction: the retirement-plan deduction had been capped only at the lesser of the §415(c) limit and net earnings, so an entry above a plan's real ceiling was accepted (an external review entered $100,000 on $72,000 of profit and got a $66,913 deduction). The calculator now distinguishes SEP-IRA and solo 401(k), applies the 20% self-employed rate, the §402(g) deferral less deferrals made in another employer's plan, the §415(c) cap and the age-based catch-ups, and reduces an excess entry to the plan-specific maximum with a note. Earlier text in this file saying age and plan type were not collected no longer applies. 2026-09-08 correction: the quarterly calculator had taken one 'paid so far' figure, which could not show whether past installments were met and treated withholding and estimated payments alike; the §6654(e)(1) $1,000 test also subtracted estimated payments, which the statute does not. It now credits withholding one quarter per due date (§6654(g)), each estimated payment on its date to the oldest unpaid installment (§6654(b)(3)), reports each installment's status, and estimates the penalty accrued at the §6621 rates; the $1,000 test uses withholding only. 2026-09-09 correction: the solo 401(k) maximum ignored the §415(c)(1)(B) 100%-of-compensation limit, which for a self-employed person makes each dollar of employer contribution cost two dollars of headroom (compensation is net earnings less the employer contribution, with elective deferrals added back). Between about $26,400 and $43,900 of net profit the old figure was too high — at about $32,300 of profit it allowed about $30,000 where Pub. 560's worksheet allows about $27,250 (2026 limits; the exact figures depend on the self-employment tax). The engine now follows the worksheet: deferral, then employer ≤ (net earnings − deferral) ÷ 2, then catch-up ≤ compensation − deferrals; the ceiling is reported as three components that add to the total. Two independent primary-source reads (Pub. 560 worksheet steps 11–13 and the §415/§404/§414 text) agreed on the rule. §401(a)(17) compensation limit added for the employer 25%-of-capped-compensation ceiling. 2026-09-09 (red team): two further corrections to the same worksheet. Each component is now settled to the cent as it is computed, so the catch-up sees the cent released by flooring the employer contribution (at $40,000 of profit with a catch-up it is $6,337.05, not $6,337.04) and the three parts add to the total exactly. And catch-up contributions made in another employer's plan now reduce what is left here: the §414(v) amount is one per individual across employers (Treas. Reg. §1.402(g)-2). An adversarial pass recomputed all 79 combinations of profit, age band and prior deferrals by hand from the worksheet; the remaining differences from a hand-worked Form 1040 are that the worksheet's inputs are whole dollars where this engine keeps cents, and that the ceiling assumes an entirely pre-tax contribution (designated Roth amounts count against it without being deductible). Both are stated on the methodology page. 2026-09-09 correction: the underpayment-penalty estimate was reported even where the statute removes the addition to tax outright — §6654(e)(1) (tax under $1,000 after withholding) and §6654(e)(2) (a full twelve-month prior year with no tax). It is now omitted in both cases, so a page can no longer show an accrued penalty and the reason it cannot arise at the same time. 2026-09-09 correction: the $1,000 floor was treated as a defence against the penalty only, so a filer expecting to owe less than that after withholding was still shown a required annual payment, installments marked short and advice to catch up — while being told no penalty could arise. Form 1040-ES's General Rule makes it a condition of the requirement itself ('you must pay estimated tax if BOTH of the following apply: 1. you expect to owe at least $1,000 after subtracting your withholding and refundable credits'), so the requirement and the whole schedule are now zero, as they already were for the §6654(e)(2) prior-year exception. Estimated payments already made do not count towards the test; only withholding and refundable credits do. 2026-09-10: the aged additional standard deduction and the 2025–2028 senior deduction added for the retirement withdrawal calculator. Two independent reads (a red-team agent and the lead, both from rp-25-32 and the enrolled text of P.L. 119-21) agree on every figure; the senior deduction is taken per qualified individual and each individual's $6,000 is reduced by the same 6% of the excess MAGI, which Schedule 1-A (2025) lines 35–37 confirm; it reduces taxable income below AGI, so it does not enter the §86 computation. 2026-09-17 correction: the §199A deduction applied the 20%-of-taxable-income cap before the phase-in reduction (20% × min(QBI, taxable income) × phase factor) instead of after it (min(20% × QBI × phase factor, 20% × taxable income)), the order §199A(a)(2) and (b)(3)(B) prescribe and Form 8995-A works in Parts III and IV. Every sole proprietor with no other income whose taxable income fell inside the phase-in range was shown too small a deduction and too much tax: for a single filer with $250,000 of profit and nothing else, $33,677.24 became $36,151.78 and the income tax fell by $593.89. The engine test that pinned the old order was corrected, and a line-by-line Form 8995-A implementation now checks 17 hand-worked cases and a grid across both years and all four statuses. The methodology page described the wrong order in the same words and was rewritten. Found by an external review on 2026-09-17. 2026-09-17 correction: the Additional Medicare Tax on W-2 wages above the filing-status threshold (Form 8959 Part I, 0.9%) was left out of the federal total; only the part on net earnings from self-employment (Part II) was counted, although the methodology page said both were. A single filer with $300,000 of wages and no profit was shown $0 of Additional Medicare Tax instead of $900; with $100,000 of profit as well, $831.15 instead of $1,731.15. The 1099 vs W-2 comparison understated the W-2 side's payroll tax by the same amount. The engine now returns the wage part separately, the federal total and the comparison include it, and the breakdown shows it as its own line (the employer withholds it, so a filer who enters the tax withheld from wages already has it covered). Found by an external review on 2026-09-17. 2026-09-17 correction: the estimated tax underpayment charge kept accruing past the return's due date. §6654(b)(2) runs each underpayment from its installment date to the earlier of the date paid and the 15th day of the fourth month after the year ends, so for a 2026 underpayment nothing accrues after 15 April 2027; the engine used today's date without that ceiling, and a link dated later showed a larger figure ($744.26 on 15 May 2027 against $661.41 on 15 April, on $16,000 of unpaid tax). The charge now stops on that day, the per-day figure is zero from then, and the quarterly and penalty pages say that interest and the late-payment penalty on the unpaid tax take over, which they do not estimate. Found by an external review on 2026-09-17. 2026-09-18: two inputs added after an external review. A spouse's W-2 wages on a joint return now count in AGI, in earned income for the credits, towards the Additional Medicare Tax threshold (Form 8959 combines both spouses' wages) and in state income, but not against the filer's own Social Security wage base, which is per person; before, the only wages box was the filer's, so a spouse's wages either went unentered or wrongly used up the filer's base (up to $11,451.40 of self-employment tax in 2026). And children aged 17 to 23 who qualify for the earned income credit (under 19, a full-time student under 24, or disabled) can now be counted for it; before, only the under-17 count fed the credit. Both are inputs the calculator did not have rather than figures it got wrong.
California 2025	verified	2026-09-08	California FTB 2025 Form 540 Tax Rate Schedules (Schedules X, Y, Z) FTB Tax News, October 2025 : 2025 indexing: standard deduction, exemption credits (CCPI factor 3.0%) 2025 Form 540 Booklet, line 62 : Behavioral Health Services Tax (1% over $1,000,000 taxable income) 2025 Schedule CA (540) instructions, Part I Section C line 15 : no adjustment to the federal ½-SE-tax deduction Franchise Tax Board : 2025 FTB 3514 instructions and the 2025 California earned income tax credit table (658 rows): CalEITC for earned income (net profit less the deductible half of self-employment tax, plus wages — Worksheet 3, lines 18–19) under $32,901, maximum $302 / $2,016 / $3,339 / $3,756 for 0 / 1 / 2 / 3+ qualifying children, childless filers from age 18 with no upper limit, investment income up to $4,814; young child tax credit of $1,189 per return with a qualifying child under 6, reduced $21.71 per $100 of earned income over $27,425; R&TC §17052 (two-stage credit with the 0.85 adjustment factor) and §17052.1 2026 Form 540-ES instructions, "Payment amounts" : estimated tax is paid 30% by April 15, 40% by June 15, 0% by September 15 and 30% by January 15 (R&TC §19136.1) Verification: Two independent primary-source reads on 2026-09-05 (state 2025 form instructions / rate schedules, statute or enacted 2025 legislation), reconciled; every difference from the draft corrected and logged in notes. California's working-family credits were added 2026-09-08 after two independent reads of the 2025 FTB 3514 instructions and table and R&TC §17052 / §17052.1; the test suite pins seven table cells, the maxima and the last row. Notes 2026-09-05 audit: all 24 bracket thresholds replaced. The draft had scaled the prior-year schedule by the wrong inflation factor (~2.3% instead of the FTB's 3.0%); single/MFS, joint and head-of-household schedules now match FTB Schedules X, Y and Z exactly. Standard deduction and exemption credits were already correct. Exemption credits phase out at high income ($6 per exemption for each $2,500 of federal AGI over $252,203 single/MFS, $504,411 joint, $378,310 HoH) — not modeled; overstates credits by at most $153 + $475 per dependent for those filers. The 1% tax on taxable income over $1,000,000 was renamed Behavioral Health Services Tax for 2025; the JSON key keeps the former name. California does not allow the federal §199A deduction; because it is below-the-line federally it never enters CA AGI, so no adjustment is needed. 2026 California figures are published by the FTB in late 2026; until then sites fall back to this file and say so. State credits (2026-09-08, two independent reads reconciled): the CalEITC is recomputed from California earned income rather than taken as a share of the federal credit. The engine carries the two-stage §17052 formula with parameters fitted to the FTB table (the first stage from the booklet's percentages and earned-income amounts; the second stage's phase-out slopes fitted so that every table cell for one and two children, and all but two cells for none and three or more, reproduce exactly) and reads it at the midpoint of the table's $50 income band, as the table does. The young child tax credit is one per return, needs a CalEITC of at least $1 and a child under 6, and is reduced $21.71 for every $100 (in decimals) of earned income over $27,425, never below $1 while eligible. Both are refundable. Not modeled: the foster youth tax credit, the zero-earned-income route to the young child credit, and the AGI test's federal-AGI variant for filers with unearned income. 2026: no amounts published yet. 2026-09-08: added the 30/40/0/30 installment split so quarterly figures stop assuming four equal California payments. The split has been unchanged since 2010 (R&TC §19136.1); the $500 ($250 married filing separately) threshold and the FTB's own due dates are described on the page, not computed.
Alabama 2025	verified	2026-09-08	Alabama Department of Revenue : 2025 Form 40 booklet: tax rate schedule and tax table (rows 50,000–50,100: $2,463 single / $2,423 joint; over-$100,000 worksheet 5% × excess + $4,958 / $4,918), standard deduction chart p.9, dependent exemption tiers, personal exemptions, federal income tax deduction worksheet (Form 40 line 12), Part II adjustments list, filing thresholds Alabama Department of Revenue : individual income tax rates / FAQ page (2%, 4%, 5% brackets at $500 and $3,000; $1,000 and $6,000 joint) Code of Alabama §40-18-15(b)(4) (standard deduction step rule), read as restated verbatim in the enrolled H.B. 527 of 2026 on ALISON; the rate section §40-18-5 and the exemption section §40-18-19 were not read directly (the Code database blocks automated access) : their amounts rest on the Department's booklet and rates page Alabama Department of Revenue : 2025 Form 40 booklet, lines 17–27 and Schedule OC: no earned income credit, child credit or low-income credit exists; the federal EIC and additional child tax credit only reduce the federal income tax deduction Alabama Department of Revenue : 2025 Form 40 booklet, p.8 (line 9: self-employed persons may deduct health insurance premiums to the same extent as allowed for federal purposes) and p.16, Part II line 2 (Keogh retirement plan and SEP deduction: contributions to a Keogh plan deductible from gross income, including qualified SEP contributions) and line 7 (self-employed health insurance deduction); 2025 Form 40 p.2, Part II lines 2 and 7 IRS Publication 560 : a qualified plan that covers a self-employed individual is a Keogh (H.R. 10) plan — the basis for taking a one-participant 401(k) on Alabama's Keogh line Verification: Two independent reads on 2026-09-07 of the 2025 Form 40 booklet and Department pages (the second reader blind to the first's report), reconciled, then attacked by a third reader who recomputed five taxpayers by hand from the booklet and matched the engine to the cent; every standard-deduction band was compared with the statutory step rule and the two reads agreed on all 84 bands. The booklet's worked example ($23,360 taxable → $1,088 joint / $1,128 single), the 50,000–50,100 table row and the over-$100,000 worksheet are reproduced in the test suite. State credits reviewed 2026-09-08 by two independent readers of the Form 40 booklet: none exist. Notes 2026-09-07 audit: rates, deduction chart, exemptions and the federal income tax deduction worksheet confirmed by both readers; the draft had every figure right. H.B. 389 of 2025 (which would have raised the standard deduction and dependent tiers) was not enacted — the 2026 act restates the 2022 amounts. Alabama computes its own adjusted gross income (Form 40 Part II lists every adjustment; none is the federal deduction for one-half of self-employment tax), so state AGI = net profit + wages. Self-employment tax is deductible only by itemizers, and only the amount paid during the year for prior years (Schedule A line 6); not modeled. The federal §199A (QBI) deduction is not adopted (ALDOR's federal-conformity analysis marks §199A as not tied). Itemizing usually beats Alabama's small standard deduction for a sole proprietor: self-employment tax paid during the year (the prior year's balance and this year's estimates) is deductible on Schedule A line 6, worth roughly $75–$275 of state tax at $40,000–$150,000 of profit. The calculator uses the standard deduction and says so on the page. Federal income tax deduction (Form 40 line 12 worksheet): Form 1040 line 22 (income tax after nonrefundable credits) plus the net investment income tax, less refundable credits (EIC, additional child tax credit, American opportunity, refundable adoption, Form 2439). Self-employment tax is excluded. No cap. The engine deducts income tax after nonrefundable credits less the refundable credits it models (ACTC, EITC). Standard deduction chart (booklet p.9, statute §40-18-15(b)(4)): keyed on Alabama AGI in completed $500 steps ($250 for married filing separately) — joint $8,500 falling by $175 per step from $26,000 to a $5,000 floor at $35,500; single $3,000 falling by $25 to $2,500; head of family $5,200 falling by $135 to $2,500; separate $4,250 falling by $88 per $250 from $13,000 to $2,500 at $17,750. The booklet's joint column misprints one band as '$25,500 – $26,999'; the tier boundaries here follow the surrounding rows and the statute's step rule. Tier limits are written as whole dollars because the chart is; the return is filed in whole dollars. Dependent exemption tiers by Alabama AGI: $1,000 (AGI up to $50,000), $500 ($50,001–$100,000), $300 (over $100,000); the same amount applies to any dependent, not only children. Personal exemption $1,500 single/separate, $3,000 joint (written as $1,500 per spouse, the engine counting two filers) and $3,000 head of family. Tax above $100,000 of taxable income follows the booklet's over-$100,000 worksheet — 5% of the excess plus $4,958 ($4,918 joint) — whose constants are the tax-table values at the $99,950 midpoint, $2 below the strict 2%/4%/5% arithmetic. The engine reproduces the worksheet with a −$2 step from $100,000 up (the table's last row, 99,900–100,000, prints the same $4,958), so filers on either side of the line get the figure the Department's own instructions produce. Filing thresholds ($4,500 single, $5,750 separate, $8,200 head of family, $11,500 joint) are gross-income tests; below them the deductions already zero out the tax. Not modeled: itemized deductions, the SE-tax itemized deduction, the 2025 overtime exemption (W-2 overtime only, through 2025-06-30) and the 2026–2028 overtime deduction (H.B. 527 of 2026, wages only, up to $1,000), Alabama's dependent care and other credits. State credits (2026-09-08, two independent reads reconciled): Alabama has no earned income, child or low-income credit. 2026-09-18 correction: the self-employed health insurance premium and SEP-IRA / solo 401(k) contributions were refused, although Form 40 Part II takes both as adjustments to income: line 2 'Payments to a Keogh retirement plan and self-employment SEP deduction' (booklet p.16: self-employed individuals may deduct contributions to a Keogh plan from gross income, including qualified SEP contributions) and line 7 'Self-employed health insurance deduction … to the same extent as allowed for federal purposes' (booklet pp.8 and 16). A one-participant 401(k) is a qualified plan covering a self-employed individual, which is what Publication 560 calls a Keogh (H.R. 10) plan, so it is taken on line 2. Both come off before Alabama AGI (line 10), so the sliding standard deduction and the dependent tiers see them; the filing thresholds stay gross-income tests. Found by the 2026-09-17 audit's follow-up.
Alabama 2026	verified	2026-09-08	Enrolled H.B. 527 of 2026 (Act adding the 2026–2028 overtime deduction), which restates Code of Alabama §40-18-15(b) in full with the 2022+ standard deduction amounts unchanged : read as ALISON's bill PDF on 2026-09-07 Alabama Department of Revenue : 2025 Form 40 booklet (rates, tax table, exemption tiers, federal income tax deduction worksheet), none of which is indexed; the 2026 booklet is not yet published Alabama Department of Revenue : individual income tax rates / FAQ page Alabama Department of Revenue : 2025 Form 40 booklet, lines 17–27 and Schedule OC: no earned income credit, child credit or low-income credit exists; the federal EIC and additional child tax credit only reduce the federal income tax deduction Alabama Department of Revenue : 2025 Form 40 booklet, p.8 (line 9: self-employed persons may deduct health insurance premiums to the same extent as allowed for federal purposes) and p.16, Part II line 2 (Keogh retirement plan and SEP deduction: contributions to a Keogh plan deductible from gross income, including qualified SEP contributions) and line 7 (self-employed health insurance deduction); 2025 Form 40 p.2, Part II lines 2 and 7 IRS Publication 560 : a qualified plan that covers a self-employed individual is a Keogh (H.R. 10) plan — the basis for taking a one-participant 401(k) on Alabama's Keogh line Verification: Two independent reads on 2026-09-07 (the second blind to the first) established that no 2026 amount changes: Alabama does not index its brackets, deductions or exemptions, H.B. 389 of 2025 was not enacted, and the only 2026 legislation (H.B. 527) adds an overtime deduction for wage earners. The 2025 figures therefore carry into 2026; re-read against the 2026 Form 40 booklet when it appears. State credits reviewed 2026-09-08 by two independent readers of the Form 40 booklet: none exist. Notes 2026-09-07: identical to 2025 by statute; H.B. 527 of 2026 restates §40-18-15(b) with the same amounts. The 2026 booklet's tax table and over-$100,000 worksheet are expected to repeat the 2025 constants. Alabama computes its own adjusted gross income (Form 40 Part II lists every adjustment; none is the federal deduction for one-half of self-employment tax), so state AGI = net profit + wages. Self-employment tax is deductible only by itemizers, and only the amount paid during the year for prior years (Schedule A line 6); not modeled. The federal §199A (QBI) deduction is not adopted (ALDOR's federal-conformity analysis marks §199A as not tied). Itemizing usually beats Alabama's small standard deduction for a sole proprietor: self-employment tax paid during the year (the prior year's balance and this year's estimates) is deductible on Schedule A line 6, worth roughly $75–$275 of state tax at $40,000–$150,000 of profit. The calculator uses the standard deduction and says so on the page. Federal income tax deduction (Form 40 line 12 worksheet): Form 1040 line 22 (income tax after nonrefundable credits) plus the net investment income tax, less refundable credits (EIC, additional child tax credit, American opportunity, refundable adoption, Form 2439). Self-employment tax is excluded. No cap. The engine deducts income tax after nonrefundable credits less the refundable credits it models (ACTC, EITC). Standard deduction chart (booklet p.9, statute §40-18-15(b)(4)): keyed on Alabama AGI in completed $500 steps ($250 for married filing separately) — joint $8,500 falling by $175 per step from $26,000 to a $5,000 floor at $35,500; single $3,000 falling by $25 to $2,500; head of family $5,200 falling by $135 to $2,500; separate $4,250 falling by $88 per $250 from $13,000 to $2,500 at $17,750. The booklet's joint column misprints one band as '$25,500 – $26,999'; the tier boundaries here follow the surrounding rows and the statute's step rule. Tier limits are written as whole dollars because the chart is; the return is filed in whole dollars. Dependent exemption tiers by Alabama AGI: $1,000 (AGI up to $50,000), $500 ($50,001–$100,000), $300 (over $100,000); the same amount applies to any dependent, not only children. Personal exemption $1,500 single/separate, $3,000 joint (written as $1,500 per spouse, the engine counting two filers) and $3,000 head of family. Tax above $100,000 of taxable income follows the booklet's over-$100,000 worksheet — 5% of the excess plus $4,958 ($4,918 joint) — whose constants are the tax-table values at the $99,950 midpoint, $2 below the strict 2%/4%/5% arithmetic. The engine reproduces the worksheet with a −$2 step from $100,000 up (the table's last row, 99,900–100,000, prints the same $4,958), so filers on either side of the line get the figure the Department's own instructions produce. Filing thresholds ($4,500 single, $5,750 separate, $8,200 head of family, $11,500 joint) are gross-income tests; below them the deductions already zero out the tax. Not modeled: itemized deductions, the SE-tax itemized deduction, the 2025 overtime exemption (W-2 overtime only, through 2025-06-30) and the 2026–2028 overtime deduction (H.B. 527 of 2026, wages only, up to $1,000), Alabama's dependent care and other credits. State credits (2026-09-08, two independent reads reconciled): Alabama has no earned income, child or low-income credit. 2026-09-18 correction: the self-employed health insurance premium and SEP-IRA / solo 401(k) contributions were refused, although Form 40 Part II takes both as adjustments to income: line 2 'Payments to a Keogh retirement plan and self-employment SEP deduction' (booklet p.16: self-employed individuals may deduct contributions to a Keogh plan from gross income, including qualified SEP contributions) and line 7 'Self-employed health insurance deduction … to the same extent as allowed for federal purposes' (booklet pp.8 and 16). A one-participant 401(k) is a qualified plan covering a self-employed individual, which is what Publication 560 calls a Keogh (H.R. 10) plan, so it is taken on line 2. Both come off before Alabama AGI (line 10), so the sliding standard deduction and the dependent tiers see them; the filing thresholds stay gross-income tests. Found by the 2026-09-17 audit's follow-up.
Arizona 2025	verified	2026-09-08	Arizona Department of Revenue : 2025 Form 140 instructions A.R.S. §43-1011 (2.5% flat rate), §43-1041 (standard deduction conforms to federal), §43-1073.01 (dependent tax credit) Arizona Department of Revenue : 2025 Form 140 instructions: line 49 dependent tax credit ($100 per dependent under 17, $25 per dependent 17 and over, nonrefundable, reduced by Table V — 5% per $1,000 of federal AGI over $200,000, $400,000 joint, gone past $19,000 over), line 50 family income tax credit ($40 per person, capped $240 / $120, for incomes under a table that sits below the standard deduction for most statuses), line 56 increased excise tax credit ($25 per person up to $100 per household, refundable, federal AGI up to $25,000 joint and head of household / $12,500 single and separate); A.R.S. §43-1073 Verification: Two independent primary-source reads on 2026-09-05 (state 2025 form instructions / rate schedules, statute or enacted 2025 legislation), reconciled; every difference from the draft corrected and logged in notes. State credits reviewed 2026-09-08 by two independent readers of the 2025 Form 140 instructions; the excise credit was added and the family income tax credit documented as not modeled. Notes 2026-09-05 audit: 2.5% rate, standard deduction and dependent credit confirmed against the 2025 Form 140 instructions and A.R.S. §43-1073.01. The 2025 standard deduction equals the OBBBA-amended federal amounts by virtue of H.B. 4168 (Laws 2026, signed 2026-06-13), which set $15,750/$23,625/$31,500 retroactively for 2025. Added the credit phase-out: 5% for each $1,000 or fraction of federal AGI over $200,000 ($400,000 joint), gone once the excess exceeds $19,000. For 2026 the under-17 dependent credit rises to $125 (H.B. 4168); a 2026 file is needed. Not modeled: the standard-deduction increase equal to 34% of charitable contributions, and the 2025 tips/overtime subtractions. State credits (2026-09-08, two independent reads reconciled): Arizona has no earned income credit. The dependent tax credit ($100 per dependent under 17, $25 for others) is already carried as the engine's dependent credit; the refundable increased excise tax credit ($25 per person, up to $100, for federal AGI up to $25,000 joint and head of household or $12,500 single and separate) is now applied. The family income tax credit is not modeled: its income limits ($10,000 single; $20,000–$31,000 joint by dependents) fall below the standard deduction, so it reaches only head-of-household filers with three or more dependents. 2026: the enacted omnibus (Ch. 140 of 2026) raises the under-17 dependent credit to $125, retroactive to 2026 — no Arizona 2026 file exists yet, so the 2026 estimate uses $100.
Colorado 2025	verified	2026-09-08	Colorado Department of Revenue : 2025 Individual Income Tax Guide / 104 Book (rev. 2025-12-30, read from a forms mirror because tax.colorado.gov blocks automated access): line 1 = federal taxable income (Form 1040 line 15), line 3 qualified business income deduction addback (federal AGI over $500,000 / $1,000,000 joint), line 4 deduction addback (AGI over $300,000; deductions over $12,000 / $16,000), 'The income tax rate is currently 4.4%', tax table rows 9,900–10,000 → $438, 29,900–30,000 → $1,318, 49,900–50,000 → $2,198, over-$50,000 worksheet 'multiply by 4.4%' C.R.S. §39-22-104(1.7)(c) (starting point), (3)(o) (QBI addback), (3)(p.5) (deduction addback) and (3)(s) (business-meals addback, 2024–2030); S.B. 24-228 (the temporary rate-reduction mechanism; the fiscal-year 2024-25 surplus fell below its $300 million trigger, so 4.4% applies to 2025); H.B. 25B-1001 (signed 2025-08-28) striking the 2026 sunset of the QBI addback; §39-22-103(5.3) (rolling conformity) Colorado Department of Revenue : 2025 DR 0104CR line 5 (Colorado earned income tax credit: 50% of the federal credit, refundable) and 2025 DR 0104CN Sections B and C: the child tax credit per child under 6 ($1,200 / $600 / $200 at federal AGI up to $26,000 / $51,000 / $77,000; $36,000 / $61,000 / $87,000 joint; refundable) and the family affordability tax credit (per child under 6 from $3,273 down to $123, per child 6–16 from $2,455 down to $92, across fifteen $5,000 bands of federal AGI up to $85,000, $96,000 joint; refundable; stacks with the child tax credit); C.R.S. §39-22-123.5 as amended by H.B. 24-1134 and §39-22-129 Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the 104 Book and the enacted H.B. 25B-1001 text, reconciled with no differences, then attacked by a third reader who recomputed eight returns by hand and matched the engine to the cent. Tax-table rows are reproduced in the test suite. State credits added 2026-09-08 after two independent reads of DR 0104CR, DR 0104CN and the statute. Notes 2026-09-07 audit: the 4.4% rate (not the temporary 4.25% of 2024), the starting point and both addbacks confirmed by both readers; a web-search summary offering $250,000 / $500,000 QBI thresholds was wrong. Colorado taxable income starts from FEDERAL taxable income (DR 0104 line 1 = Form 1040 line 15), so the federal standard deduction and the §199A (QBI) deduction already apply and the federal deduction for one-half of self-employment tax stays in. The engine passes the federal figure through, then applies the two addbacks: the whole QBI deduction when federal AGI exceeds $500,000 ($1,000,000 joint), and the part of the federal standard deduction above $12,000 ($16,000 joint) when AGI exceeds $300,000. There is no Colorado standard deduction, no personal or dependent exemption, and no local income tax (some cities charge a flat occupational privilege tax of a few dollars a month). The deduction addback applies to AGI 'equal to or exceeding $300,000' (statute) — the engine's threshold is written as $299,999.99 so that exactly $300,000 is included. State credits (2026-09-08, two independent reads reconciled): the Colorado EITC (50% of the federal credit), the child tax credit per child under 6 and the 2025 family affordability credit per child (under 6 and 6–16 tables) are applied, all refundable; the 'children under 6' input splits the two age bands. The child and dependent care credit (50% of federal) and the under-25 / ITIN recomputation of the federal credit are not modeled.
Colorado 2026	verified	2026-09-08	Colorado Department of Revenue : 2026 Form DR 0104EP (estimated tax, rev. 2025-06-10): 'line 2: 4.4% of line 1'; 2026 DR 1098 withholding worksheet (rev. 2025-10-21): 'multiply by 4.40% (0.044)' Colorado Legislative Council Staff : June 2026 Economic & Revenue Forecast: TABOR revenue below the cap, 'the income tax rate reduction mechanism will not be triggered in tax years 2026 or 2027' H.B. 25B-1001 (2025 special session) : the QBI addback under §39-22-104(3)(o) continues indefinitely from 2026; 2025 104 Book for the unchanged mechanics C.R.S. §39-22-123.5(2)(d)(II)(C) : 25% of the federal credit for 2026 and later, plus a revenue-trigger add-on that the December 2025 OSPB forecast did not trigger — Legislative Council Staff June 2026 forecast ('the expanded EITC will be unavailable for tax year 2026') and the H.B. 26-1289 fiscal note (2026-06-12: 'for tax year 2026, the Colorado EITC is 25 percent'); §39-22-129(4.5): the child tax credit is permanent, thresholds indexed (2026 values not yet published — 2025 carried); no family affordability credit for 2026 (trigger not met; H.B. 26-1223's replacement starts 2027) Verification: Two independent reads on 2026-09-07 (the second reader blind to the first): the first read the 104 Book and H.B. 25B-1001; the second read the Department's 2026 DR 0104EP and DR 1098 and the Legislative Council Staff June 2026 forecast; the 4.4% rate for 2026 and the continued addbacks reconciled with no differences, then a third reader attacked the file and matched eight hand computations to the cent. The Department's September 2026 TABOR certification and the 2026 104 Book are not yet published. State credits added 2026-09-08 after two independent reads of §39-22-123.5 as amended, the LCS June 2026 forecast and the H.B. 26-1289 fiscal note. Notes 2026-09-07 audit: the 2026 rate confirmed from the Department 2026 forms and the June 2026 forecast; the next TABOR-triggered cut is projected for 2028. Colorado taxable income starts from FEDERAL taxable income (DR 0104 line 1 = Form 1040 line 15), so the federal standard deduction and the §199A (QBI) deduction already apply and the federal deduction for one-half of self-employment tax stays in. The engine passes the federal figure through, then applies the two addbacks: the whole QBI deduction when federal AGI exceeds $500,000 ($1,000,000 joint), and the part of the federal standard deduction above $12,000 ($16,000 joint) when AGI exceeds $300,000. There is no Colorado standard deduction, no personal or dependent exemption, and no local income tax (some cities charge a flat occupational privilege tax of a few dollars a month). The deduction addback applies to AGI 'equal to or exceeding $300,000' (statute) — the engine's threshold is written as $299,999.99 so that exactly $300,000 is included. State credits (2026-09-08, two independent reads reconciled): the Colorado EITC is 25% of the federal credit for 2026 (not the 20% of the older statute text nor 2025's 50%); the child tax credit per child under 6 continues on the 2025 thresholds pending the Department's 2026 indexation; there is no family affordability credit for 2026.
Georgia 2025	verified	2026-09-08	Georgia Department of Revenue : 2025 Form 500 instructions O.C.G.A. §48-7-20 as amended by H.B. 111 (2025) : 5.19% rate for 2025 O.C.G.A. §48-7-27 : standard deduction and dependent exemption Georgia Department of Revenue : 2025 IT-511 booklet, Form 500 line 17 low income credit (federal AGI under $20,000; per exemption — filer, spouse, natural or adopted children, plus one per spouse 65 or over — $26 under $6,000, $20 to $7,999, $14 to $9,999, $8 to $14,999, $5 to $19,999; nonrefundable, taken first) and IND-CR 202 child and dependent care credit (50% of the federal credit for 2025) Verification: Two independent primary-source reads on 2026-09-05 (state 2025 form instructions / rate schedules, statute or enacted 2025 legislation), reconciled; every difference from the draft corrected and logged in notes. State credits reviewed 2026-09-08 by two independent readers of the 2025 IT-511 booklet. Notes 2026-09-05 audit: 5.19% rate (H.B. 111 §1), $12,000/$24,000 standard deduction and $4,000 dependent exemption confirmed against the 2025 IT-511 booklet (Form 500 lines 11, 14, 16). No personal exemption for the filer exists. No figures changed. The Department of Revenue lists 4.99% and a $15,000/$30,000 standard deduction for 2026; whether the H.B. 111 revenue triggers were met was not independently confirmed — a 2026 file must cite the DOR notice. Not modeled: the child and dependent care credit (50% of the federal credit from 2025). State credits (2026-09-08, two independent reads reconciled): Georgia has no earned income credit. The low income credit (a few dollars per person for federal AGI under $20,000) is applied; the child and dependent care credit is not (no care-expense input).
Georgia 2026	verified	2026-09-08	Georgia Department of Revenue : Employer's Withholding Tax Guide 2026, revised June 2026, 'What's new for tax year 2026': H.B. 463 changes are 'retroactive to taxable years beginning on or after January 1, 2026' — rate 5.19% → 4.99%, standard deductions $30,000 MFJ and $15,000 single / head of household / MFS, dependent deduction $4,000 → $5,000 Georgia Department of Revenue : 'Important Tax Updates' page (rate 4.99%; standard deduction $15,000 single, HoH, MFS / $30,000 MFJ) Office of the Governor : press release 2026-05-11 on signing H.B. 463 (Act 465), the Georgia Economic Growth and Tax Relief Act of 2026: rate 4.99% from January 1, 2026; further 0.125-point cuts and deduction step-ups from 2027 only if revenue conditions are met O.C.G.A. §48-7-29.27 as enacted by H.B. 136 (2025) : from tax year 2026, a $250 nonrefundable credit per qualifying child (federal §24(c)) who has not attained age six, no carryforward, no income phase-out — read from the enacted text; the Department has not yet published a notice Georgia Department of Revenue : 2025 IT-511 booklet for the low income credit (unindexed) Verification: Two independent reads on 2026-09-07 of the Department of Revenue's 2026 withholding guide (June 2026 revision) and its tax-updates page, reconciled with the Governor's signing statement. The enrolled text of H.B. 463 could not be retrieved from legis.ga.gov by our tooling, so the codified O.C.G.A. §48-7-20 / §48-7-27 wording has not been read directly; re-read against the statute and the 2026 IT-511 booklet when available. State credits reviewed 2026-09-08 by two independent readers (H.B. 136 enacted text; 2025 IT-511 booklet). Notes 2026-09-07: H.B. 463 (signed 2026-05-11) cut the rate straight to 4.99% for 2026 instead of the 5.09% that the earlier trigger schedule would have allowed (the 2026 trigger was in fact not met). The Department's guide applies the higher standard deductions and the $5,000 dependent deduction to tax year 2026 as well; one legislative summary (GBPI) places the deduction increases in 2027 — the Department's published guidance is followed here. Later step-ups ($375 / $750 a year on the standard deduction, $125 on the dependent deduction, 0.125 points on the rate) start no earlier than 2027 and depend on revenue triggers; none is assumed. Georgia's standard deduction for head of household equals the single amount ($15,000); there is no personal exemption for the filer. H.B. 463 also excludes up to $1,750 each of qualified overtime and cash tips for 2026–2028; irrelevant to sole-proprietor profit and not modeled. Not modeled: the child and dependent care credit (50% of the federal credit from 2025). State credits (2026-09-08, two independent reads reconciled): from 2026 Georgia allows a $250 nonrefundable credit per child under six (H.B. 136 of 2025), applied here on the 'children under 6' input; the low income credit continues. No earned income credit.
Illinois 2025	verified	2026-09-08	Illinois Department of Revenue : 2025 Form IL-1040 instructions (rate 4.95%, line 1 = federal AGI) 2025 IL-1040 Line 10a Exemption Allowance Chart : $2,850 per person; no allowance when federal AGI exceeds $250,000 ($500,000 joint) Informational Bulletin FY 2026-15 (2026 exemption $2,925) 35 ILCS 5/201 (rate), 35 ILCS 5/204 (exemption) Illinois Department of Revenue : 2025 Form IL-1040 and Schedule IL-E/EIC instructions: line 29 Illinois earned income tax credit (20% of the federal credit as claimed, or recomputed on the expanded worksheet for ITIN filers and childless filers aged 18–24 or 65 and over; refundable) and line 30 Illinois child tax credit (40% of the Illinois EITC for a filer with a dependent qualifying child under 12, one per return, refundable — 35 ILCS 5/244, 40% for 2025 and later) Illinois Department of Revenue : 2025 Form IL-1040 and Schedule IL-E/EIC instructions: line 29 Illinois earned income tax credit (20% of the federal credit as claimed, or recomputed on the expanded worksheet for ITIN filers and childless filers aged 18–24 or 65 and over; refundable) and line 30 Illinois child tax credit (40% of the Illinois EITC for a filer with a dependent qualifying child under 12, one per return, refundable — 35 ILCS 5/244, 40% for 2025 and later; unchanged for 2026) Verification: Two independent primary-source reads on 2026-09-05 (state 2025 form instructions / rate schedules, statute or enacted 2025 legislation), reconciled; every difference from the draft corrected and logged in notes. State credits added 2026-09-08 after two independent reads of the IL-1040 instructions and 35 ILCS 5/244. Notes 2026-09-05 audit: rate and $2,850 exemption confirmed. Added the exemption cliff: the entire exemption allowance (filer and dependents) is $0 when federal AGI exceeds $250,000 (single/HoH/MFS) or $500,000 (joint). It is a cliff, not a phase-out. Not modeled: the extra $1,000 exemption for filers 65 or over or blind, and the property tax and K-12 education credits. 2026 exemption is $2,925 per Bulletin FY 2026-15; a 2026 file is needed. State credits (2026-09-08, two independent reads reconciled): the Illinois EITC is 20% of the federal credit, refundable, and the child tax credit is 40% of it for filers with a child under 12 (the calculator uses the 'children under 13' input as the test). The expanded eligibility for ITIN filers and childless 18–24 / 65+ filers recomputes a federal-style credit the calculator does not produce.
Indiana 2025	verified	2026-09-08	Indiana Department of Revenue : 2025 Form IT-40 (State Form 154, R24/9-25) and IT-40 booklet: line 1 = federal AGI (Form 1040 line 11), line 8 'multiply line 7 by 3% (.03)', worked examples p.38 ($10,000 × .03 = $300; $110,000 × .4 × .03 = $1,320) and the Sam and Molly example p.52 (exemptions $4,500 = $1,000 × 3 + $1,500; line 7 $87,000) Indiana Department of Revenue : 2025 Schedule 3 (State Form 53997, R16/9-25): $1,000 per filer, $1,000 per dependent, additional $1,500 per dependent child ($3,000 in the first year claimed), $1,000 age-65 / blindness, $500 low-income age-65, $3,000 per adopted child Indiana Department of Revenue : Departmental Notice #1 (R46/01-26) and the 'Rates, Fees & Penalties' page: 3.00% for 2025, 2.95% for 2026, 2.90% for 2027 (IC 6-3-2-1 step-downs; the statute host blocks automated access, so the rate rests on the Department's four agreeing publications) Indiana Department of Revenue : 2026 Legislative Synopsis: S.E.A. 243 (conformity date moved to 2026-01-01, retroactive to tax year 2026; 2026-only state deductions for tips, overtime and car-loan interest) and S.E.A. 212 (conformity to four 2025 federal provisions retroactive to tax year 2025) Indiana Department of Revenue : 2025 Schedule IN-EIC and IT-40 booklet: Indiana earned income credit of 10% of the federal credit as claimed, refundable, for filers who claimed the federal credit with federal AGI under $68,675 (the booklet prints $68,650); Information Bulletins #92 and #119 (computed under IRC §32 as of 2023-01-01, no practical difference) Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the IT-40, the booklet and Departmental Notice #1 — the second reader also read the Schedule 3 form itself — reconciled with no differences, then attacked by a third reader who recomputed eight returns by hand and matched the engine to the cent. The booklet's worked examples are reproduced in the test suite. IC 6-3-2-1 itself could not be retrieved from any host; the rate rests on the Department's publications. State credit added 2026-09-08 after two independent reads of Schedule IN-EIC and the booklet. Notes 2026-09-07 audit: rate, exemptions and the starting point confirmed by both readers. Indiana starts from federal AGI (IT-40 line 1 = Form 1040 line 11), so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI and is not subtracted. There is no standard deduction and federal income tax is not deductible. Exemptions (Schedule 3): $1,000 per filer ($2,000 joint), $1,000 per dependent, plus $1,500 for each dependent child ($3,000 instead in the first year the child is claimed, which the engine does not model — it uses $2,500 per child every year). Other dependents get $1,000. Federal conformity: the 2025 booklet was written on the 2023-01-01 conformity date, but S.E.A. 212 (2026) conformed retroactively to four 2025 federal provisions for tax year 2025 and S.E.A. 243 (2026) moved the conformity date to 2026-01-01 from tax year 2026, adding Indiana-only deductions for tips, overtime and car-loan interest (wage items, not modeled). None of it changes a sole proprietor's Indiana AGI as the calculator computes it — the federal QBI deduction is below the line and Indiana's own add-backs (bonus depreciation, §179 above $25,000, state income tax deducted on Schedule C) are not modeled. Not modeled: the $1,000 age-65 / blindness exemptions and the $500 low-income age-65 amount, the $3,000 adopted-child exemption, the renter's and homeowner's deductions, and the county income tax (every county, 0.5% to 3.0% for 2026, on the same base — often a third of the state bill or more). State credit (2026-09-08, two independent reads reconciled): Indiana's earned income credit is 10% of the federal credit, refundable; the federal AGI limit equals the federal credit's own phase-out, so it never binds separately. Unchanged for 2026.
Indiana 2026	verified	2026-09-08	Indiana Department of Revenue : Departmental Notice #1 (R46/01-26, effective 2026-01-01): 'For 2026, the state adjusted gross income tax rate for individuals is 2.95%'; withholding tables B and C using the unchanged $1,000 / $1,500 / $3,000 exemption amounts; county rates 0.5%–3.0% Indiana Department of Revenue : 'Rates, Fees & Penalties' page (2.95% for 2026, 2.90% for 2027) and the DOR Tax Chapter; IC 6-3-2-1 as amended by H.E.A. 1001-2023 (step-downs), text confirmed only through search snippets Indiana Department of Revenue : 2025 IT-40 and Schedule 3 for the unindexed exemption mechanics Indiana Department of Revenue : 2026 Legislative Synopsis: S.E.A. 243 (conformity date moved to 2026-01-01, retroactive to tax year 2026; 2026-only state deductions for tips, overtime and car-loan interest) and S.E.A. 212 (conformity to four 2025 federal provisions retroactive to tax year 2025) Indiana Department of Revenue : 2025 Schedule IN-EIC and IT-40 booklet: Indiana earned income credit of 10% of the federal credit as claimed, refundable, for filers who claimed the federal credit with federal AGI under $68,675 (the booklet prints $68,650); Information Bulletins #92 and #119 (computed under IRC §32 as of 2023-01-01, no practical difference) Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the IT-40, the booklet and Departmental Notice #1 — the second reader also read the Schedule 3 form itself — reconciled with no differences, then attacked by a third reader who recomputed eight returns by hand and matched the engine to the cent. The booklet's worked examples are reproduced in the test suite. IC 6-3-2-1 itself could not be retrieved from any host; the rate rests on the Department's publications. The 2026 IT-40 booklet is not yet published. State credit added 2026-09-08 after two independent reads of Schedule IN-EIC and the booklet. Notes 2026-09-07 audit: the 2.95% rate confirmed from Departmental Notice #1, the rates page and the Tax Chapter; exemptions unchanged. Indiana starts from federal AGI (IT-40 line 1 = Form 1040 line 11), so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI and is not subtracted. There is no standard deduction and federal income tax is not deductible. Exemptions (Schedule 3): $1,000 per filer ($2,000 joint), $1,000 per dependent, plus $1,500 for each dependent child ($3,000 instead in the first year the child is claimed, which the engine does not model — it uses $2,500 per child every year). Other dependents get $1,000. Federal conformity: the 2025 booklet was written on the 2023-01-01 conformity date, but S.E.A. 212 (2026) conformed retroactively to four 2025 federal provisions for tax year 2025 and S.E.A. 243 (2026) moved the conformity date to 2026-01-01 from tax year 2026, adding Indiana-only deductions for tips, overtime and car-loan interest (wage items, not modeled). None of it changes a sole proprietor's Indiana AGI as the calculator computes it — the federal QBI deduction is below the line and Indiana's own add-backs (bonus depreciation, §179 above $25,000, state income tax deducted on Schedule C) are not modeled. Not modeled: the $1,000 age-65 / blindness exemptions and the $500 low-income age-65 amount, the $3,000 adopted-child exemption, the renter's and homeowner's deductions, and the county income tax (every county, 0.5% to 3.0% for 2026, on the same base — often a third of the state bill or more). State credit (2026-09-08, two independent reads reconciled): Indiana's earned income credit is 10% of the federal credit, refundable; the federal AGI limit equals the federal credit's own phase-out, so it never binds separately. Unchanged for 2026.
Louisiana 2025	verified	2026-09-08	Louisiana Department of Revenue : 2025 Form IT-540 and instructions (line 7 federal AGI, line 8 standard deduction $12,500 / $25,000, line 11 'multiply line 10 by .03'); Revenue Information Bulletin 25-012 on the Act 11 changes Act 11 of the 2024 Third Extraordinary Session (H.B. 10) : R.S. 47:32(A) flat 3%, R.S. 47:294 standard deduction Louisiana Department of Revenue : FAQ on the repeal of the federal income tax deduction (Act 395 of 2021) Louisiana Department of Revenue : 2025 Form IT-540 line 16 and the Louisiana earned income credit worksheet (federal credit × 5%, refundable); R.S. 47:297.8 (5% for 2019–2030, 3.5% after; unchanged by any 2025 or 2026 act — the repeal and increase bills died in committee) Verification: Two independent reads on 2026-09-07 of the 2025 IT-540 instructions, RIB 25-012 and the enacted Act 11 text (the second reader blind to the first), reconciled with no differences, then attacked by a third reader who recomputed three taxpayers by hand and matched the engine. Louisiana no longer prints a tax table; the test suite pins the line arithmetic (AGI − standard deduction) × 3%. State credit added 2026-09-08 after two independent reads of the IT-540 instructions and R.S. 47:297.8. Notes 2026-09-07 audit: rate, standard deduction by filing status and the repeal of the exemptions confirmed by both readers. Act 11 of the 2024 Third Extraordinary Session (effective for tax years beginning 2025) replaced the three brackets with a flat 3% (R.S. 47:32(A)) and folded the old combined personal exemption / standard deduction and the $1,000 additional exemptions for dependents, age and blindness into one standard deduction (R.S. 47:294, retitled). No per-filer or per-dependent amount survives; the dependent lines were removed from the 2025 return. IT-540 starts from federal AGI (line 7 = Form 1040 line 11), so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI and is not subtracted. The federal income tax deduction was repealed by Act 395 of 2021 (from 2022) and not reinstated. Head of household and qualifying surviving spouse take the joint standard deduction. Not modeled: the deduction for federal itemized medical expenses above the federal standard deduction (IT-540 line 9D, itemizers only), the $12,000 retirement income exemption for filers 65 and over. State credit (2026-09-08, two independent reads reconciled): the Louisiana earned income credit is 5% of the federal credit, refundable, through 2030. The refundable child care credit (AGI up to $25,000) and school readiness credit are not modeled.
Louisiana 2026	verified	2026-09-08	Louisiana Department of Revenue : 2026 Form IT-540ES instructions (IT-540ESi): estimated tax worksheet with the 2026 standard deduction $12,875 single / married filing separately and $25,750 joint / head of household / qualifying surviving spouse, and the 3% rate Louisiana Department of Revenue : 2026 withholding notice of intent using the same $12,875 / $25,750, computed on a September-to-September CPI-U of about 3.0%, with the Department's caveat that the final amounts 'may differ slightly' once the December-to-December index is applied (the Legislative Fiscal Office's note puts that at about 2.68%, i.e. roughly $12,835 / $25,670) R.S. 47:294 as amended by Act 11 of the 2024 Third Extraordinary Session (CPI-U indexation of the standard deduction from 2026) Louisiana Department of Revenue : 2025 Form IT-540 line 16 and the Louisiana earned income credit worksheet (federal credit × 5%, refundable); R.S. 47:297.8 (5% for 2019–2030, 3.5% after; unchanged by any 2025 or 2026 act — the repeal and increase bills died in committee) Verification: Two independent reads on 2026-09-07 (the second blind to the first) of the 2026 IT-540ES instructions and the withholding notice, reconciled; both give $12,875 / $25,750. The 2026 IT-540 instructions are not yet published; re-read the indexed amounts against them when they appear. State credit added 2026-09-08 after two independent reads of the IT-540 instructions and R.S. 47:297.8. Notes 2026 amounts are provisional: they are the Department's published figures, but the Department itself expects a small downward revision (a few dollars of tax); re-read against the 2026 IT-540 instructions when issued. 2026-09-07: the first CPI-U indexation raises the standard deduction from $12,500 / $25,000 to $12,875 / $25,750; the rate stays 3%. Act 11 of the 2024 Third Extraordinary Session (effective for tax years beginning 2025) replaced the three brackets with a flat 3% (R.S. 47:32(A)) and folded the old combined personal exemption / standard deduction and the $1,000 additional exemptions for dependents, age and blindness into one standard deduction (R.S. 47:294, retitled). No per-filer or per-dependent amount survives; the dependent lines were removed from the 2025 return. IT-540 starts from federal AGI (line 7 = Form 1040 line 11), so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI and is not subtracted. The federal income tax deduction was repealed by Act 395 of 2021 (from 2022) and not reinstated. Head of household and qualifying surviving spouse take the joint standard deduction. Not modeled: the deduction for federal itemized medical expenses above the federal standard deduction (IT-540 line 9D, itemizers only), the $12,000 retirement income exemption for filers 65 and over. State credit (2026-09-08, two independent reads reconciled): the Louisiana earned income credit is 5% of the federal credit, refundable, through 2030. The refundable child care credit (AGI up to $25,000) and school readiness credit are not modeled.
Massachusetts 2025	verified	2026-09-08	Massachusetts Department of Revenue : 2025 Form 1 instructions (read from the Wayback Machine copy of mass.gov and an identical taxformfinder mirror): 5% rate and tax table (rows 9,950–10,000 → $499; 23,950–24,000 → $1,199; multiply by .05 above $24,000), 4% surtax on taxable income over $1,083,150 (p.3, line 28b), personal exemptions line 2a ($4,400 / $8,800 / $6,800), dependents line 2b ($1,000 each), line 11 deduction for Social Security / Medicare / self-employment tax up to $2,000 per person, Schedule Y line 9a excluding federal Schedule 1 lines 12–23, No Tax Status and Limited Income Credit worksheets (line 29) Massachusetts Department of Revenue : tax rates page (updated 2025-12-30) and TIR 23-1 (c.62 §2(d)(1)(Q): the §199A deduction is not allowed); M.G.L. c.62 §3 (exemptions) and §2(d)(1)(Q) as quoted in TIR 23-1 — the rate section §4 was not read directly; the rate and surtax rest on the Department's forms Massachusetts Department of Revenue : 2025 Form 1 instructions, line 43 (earned income credit: 40% of the federal credit on Form 1040 line 27a, refundable) and line 46 (child and family tax credit: $440 per dependent under 13, or 65+ / disabled, no phase-out, no cap, refundable; not for married filing separately); M.G.L. c.62 §6(h) and §6(x) Massachusetts Department of Revenue : 'Massachusetts Medical-Related Deductions' page (read 2026-09-18): self-employed persons may deduct from Massachusetts gross income amounts paid for health insurance to the extent allowed under IRC §162(l), limited to earned income from the trade or business Massachusetts Department of Revenue : 2025 Form 1 instructions, Schedule Y line 7 (self-employed health insurance: the amount from U.S. Form 1040 Schedule 1 line 17) Massachusetts Department of Revenue : 'Massachusetts Gross, Adjusted Gross, and Taxable Income' page (updated 2024-12-20): Massachusetts AGI = federal gross income ± Schedule B and D adjustments − Schedule Y lines 1–10; No Tax Status and the Limited Income Credit key on it Massachusetts Department of Revenue : 'Tax Treatment of Non-Government Pensions in Massachusetts' page (updated 2026-04-03): §404 deductions for contributions on behalf of partners and owners of sole proprietorships are not allowed (401(k) plans of a sole proprietorship included); Keogh (HR-10) contributions are made with after-tax dollars and are not deductible Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the Form 1 instructions, the 2026 Form 1-ES, the DOR rates page and TIR 23-1, reconciled with no differences, then attacked by a third reader who recomputed eight returns by hand and matched the engine to the dollar; mass.gov blocks automated access, so both readers used archived copies of the Department's PDFs (the same revision codes the Department lists). Tax-table rows, the No Tax Status thresholds and the Limited Income Credit worksheet are reproduced in the test suite. State credits added 2026-09-08 after two independent reads of the Form 1 instructions. Notes 2026-09-07 audit: rate, surtax threshold, exemptions, the line 11 cap and both low-income provisions confirmed by both readers. Massachusetts builds its own income (Form 1 Schedule C), so the federal deduction for one-half of self-employment tax is not allowed (Schedule Y line 9a excludes federal Schedule 1 lines 12–23). Instead line 11 deducts Social Security, Medicare and self-employment tax actually paid, up to $2,000 per person; the engine deducts the lesser of the year's self-employment tax and $2,000. The federal §199A (QBI) deduction is disallowed (c.62 §2(d)(1)(Q)). The 4% surtax applies to the part of taxable income over the threshold and is modeled as a 9% top bracket; the same threshold applies to every filing status. Personal exemption $4,400 single and separate, $8,800 joint (written as $4,400 per spouse), $6,800 head of household; $1,000 per dependent. No standard deduction. No Tax Status: no tax when Massachusetts AGI is at or below $8,000 (single), $14,400 plus $1,000 per dependent (head of household), $16,400 plus $1,000 per dependent (joint); not available to married filing separately. Just above those lines the Limited Income Credit caps the tax at 10% of the AGI over the threshold (Form 1 line 29 worksheet). State credits (2026-09-08, two independent reads reconciled): the earned income credit is 40% of the federal credit, refundable, applied last; married filing separately cannot claim it (except under a domestic-abuse exception the calculator does not model). The child and family tax credit is $440 per dependent under 13 — the calculator counts the 'children under 13' input — and also covers dependents 65 or over and disabled dependents, which it does not. 2026: no enacted change to either credit (bills raising them to 50% and $600 are pending); re-read the 2026 Form 1 instructions when published. 2026-09-18 correction: the self-employed health insurance premium was refused along with the retirement contributions. Massachusetts allows it: Schedule Y line 7 takes the amount from U.S. Schedule 1 line 17 (2025 Form 1 instructions), and the Department's medical-deductions page states the §162(l) deduction from Massachusetts gross income, limited to earned income from the business. Schedule Y lines 1–10 are subtracted in reaching Massachusetts AGI, so the premium also counts for No Tax Status and the Limited Income Credit. SEP-IRA and solo 401(k) contributions remain refused: the Department's non-government pensions page says §404 deductions for contributions on behalf of owners of sole proprietorships are not allowed (including a sole proprietorship's 401(k)) and Keogh contributions are made with after-tax dollars. Found by the 2026-09-17 audit's follow-up.
Massachusetts 2026	verified	2026-09-08	Massachusetts Department of Revenue : 2026 Form 1-ES instructions (Wayback copy): 5% rate and the 4% surtax on taxable income over $1,107,750 for 2026; DOR tax rates page (updated 2025-12-30) with the same 2026 threshold Massachusetts Department of Revenue : 2025 Form 1 instructions for every unindexed amount (exemptions, dependents, the $2,000 line 11 cap, No Tax Status and Limited Income Credit thresholds), none of which the statute indexes; TIR 26-4 (2026-06-23) confirming non-conformity to the 2025 federal QBI, tips and overtime provisions (St. 2026 c.101) M.G.L. c.62 §3 (exemptions) and §2(d)(1)(Q) via TIR 23-1; the rate section §4 was not read directly Massachusetts Department of Revenue : 2025 Form 1 instructions, line 43 (earned income credit: 40% of the federal credit on Form 1040 line 27a, refundable) and line 46 (child and family tax credit: $440 per dependent under 13, or 65+ / disabled, no phase-out, no cap, refundable; not for married filing separately); M.G.L. c.62 §6(h) and §6(x) Massachusetts Department of Revenue : 'Massachusetts Medical-Related Deductions' page (read 2026-09-18): self-employed persons may deduct from Massachusetts gross income amounts paid for health insurance to the extent allowed under IRC §162(l), limited to earned income from the trade or business Massachusetts Department of Revenue : 2025 Form 1 instructions, Schedule Y line 7 (self-employed health insurance: the amount from U.S. Form 1040 Schedule 1 line 17) Massachusetts Department of Revenue : 'Massachusetts Gross, Adjusted Gross, and Taxable Income' page (updated 2024-12-20): Massachusetts AGI = federal gross income ± Schedule B and D adjustments − Schedule Y lines 1–10; No Tax Status and the Limited Income Credit key on it Massachusetts Department of Revenue : 'Tax Treatment of Non-Government Pensions in Massachusetts' page (updated 2026-04-03): §404 deductions for contributions on behalf of partners and owners of sole proprietorships are not allowed (401(k) plans of a sole proprietorship included); Keogh (HR-10) contributions are made with after-tax dollars and are not deductible Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the Form 1 instructions, the 2026 Form 1-ES, the DOR rates page and TIR 23-1, reconciled with no differences, then attacked by a third reader who recomputed eight returns by hand and matched the engine to the dollar; mass.gov blocks automated access, so both readers used archived copies of the Department's PDFs (the same revision codes the Department lists). Tax-table rows, the No Tax Status thresholds and the Limited Income Credit worksheet are reproduced in the test suite. The 2026 Form 1 instructions are not yet published; only the surtax threshold is indexed, and it is taken from the 2026 Form 1-ES. State credits added 2026-09-08 after two independent reads of the 2025 Form 1 instructions (unchanged for 2026 by statute). Notes 2026-09-07 audit: the 2026 surtax threshold ($1,107,750) confirmed from two Department publications; every other figure is unindexed statute and carried from 2025. Massachusetts builds its own income (Form 1 Schedule C), so the federal deduction for one-half of self-employment tax is not allowed (Schedule Y line 9a excludes federal Schedule 1 lines 12–23). Instead line 11 deducts Social Security, Medicare and self-employment tax actually paid, up to $2,000 per person; the engine deducts the lesser of the year's self-employment tax and $2,000. The federal §199A (QBI) deduction is disallowed (c.62 §2(d)(1)(Q)). The 4% surtax applies to the part of taxable income over the threshold and is modeled as a 9% top bracket; the same threshold applies to every filing status. Personal exemption $4,400 single and separate, $8,800 joint (written as $4,400 per spouse), $6,800 head of household; $1,000 per dependent. No standard deduction. No Tax Status: no tax when Massachusetts AGI is at or below $8,000 (single), $14,400 plus $1,000 per dependent (head of household), $16,400 plus $1,000 per dependent (joint); not available to married filing separately. Just above those lines the Limited Income Credit caps the tax at 10% of the AGI over the threshold (Form 1 line 29 worksheet). State credits (2026-09-08, two independent reads reconciled): the earned income credit is 40% of the federal credit, refundable, applied last; married filing separately cannot claim it (except under a domestic-abuse exception the calculator does not model). The child and family tax credit is $440 per dependent under 13 — the calculator counts the 'children under 13' input — and also covers dependents 65 or over and disabled dependents, which it does not. 2026: no enacted change to either credit (bills raising them to 50% and $600 are pending); re-read the 2026 Form 1 instructions when published. 2026-09-18 correction: the self-employed health insurance premium was refused along with the retirement contributions. Massachusetts allows it: Schedule Y line 7 takes the amount from U.S. Schedule 1 line 17 (2025 Form 1 instructions), and the Department's medical-deductions page states the §162(l) deduction from Massachusetts gross income, limited to earned income from the business. Schedule Y lines 1–10 are subtracted in reaching Massachusetts AGI, so the premium also counts for No Tax Status and the Limited Income Credit. SEP-IRA and solo 401(k) contributions remain refused: the Department's non-government pensions page says §404 deductions for contributions on behalf of owners of sole proprietorships are not allowed (including a sole proprietorship's 401(k)) and Keogh contributions are made with after-tax dollars. Found by the 2026-09-17 audit's follow-up.
Maryland 2025	verified	2026-09-08	Comptroller of Maryland : 2025 Resident booklet (Form 502 instructions): tax rate schedules I and II (p.22), standard deduction $3,350 / $6,700, exemption phase-down table, tax table rows (25,000–25,050 → $1,136; 50,000–50,050 → $2,324; 75,000–75,050 → $3,511; 99,950–100,000 → $4,696) and the over-$100,000 worksheets (single $200,000 → $10,010; joint $200,000 → $9,635) Md. Code, Tax-General §10-105 (rates), §10-217 (standard deduction) and §10-211 (exemptions) in their codified form as amended by Chapter 604 of 2025 (H.B. 352, Budget Reconciliation and Financing Act) : the 6.25% and 6.5% brackets and the flat standard deduction from tax year 2025; the chapter's enrolled PDF was downloaded but the text was read as codified Comptroller of Maryland : 2026 Employer Withholding Guide (pm225) and Form MW507 (2026): standard deduction $3,400 (single basis) and the unchanged exemption phase-down table; Central Payroll Bureau memo of February 2026: rates unchanged for 2026 Comptroller of Maryland : 2025 Resident booklet Instructions 18, 19 and 21 and worksheets 18A / 18A.1 / 21A: line 22 nonrefundable earned income credit (50% of the federal credit, for married filers or filers with a qualifying child), line 44 refundable earned income credit (45% of the federal credit less the Maryland tax), the 100% refundable credit for unmarried filers without a qualifying child (federal minimum age and SSN rule waived), line 29 local earned income credit; Form 502CR Part CC child tax credit ($500 per child under 6, federal AGI up to $15,000, reduced $50 per $1,000 or fraction above it, refundable); Md. Code, Tax-General §10-704 and §10-751 Verification: Two independent reads on 2026-09-07 of the 2025 booklet, the codified statute and the Comptroller's 2026 withholding publications (the second reader blind to the first), reconciled with no differences, then attacked by a third reader who recomputed four returns by hand from the booklet and matched the engine to the cent. Tax-table rows and both over-$100,000 worksheet examples are reproduced in the test suite. State credits added 2026-09-08 after two independent reads of the 2025 booklet and Form 502CR. Notes 2026-09-07 audit: both readers agree on every rate, threshold and amount. Chapter 604 of 2025 added the 6.25% ($500,001–$1,000,000 single; $600,001–$1,200,000 joint) and 6.5% brackets and replaced the 15%-of-AGI standard deduction (min/max) with flat $3,350 / $6,700 for 2025. The booklet's worksheet 17A misprints the 6.25% row's lower bound as $250,001; the schedule on p.22 and the statute say $500,001. Form 502 starts from federal AGI (line 1), so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI and is not subtracted. Federal income tax is not deductible. Exemptions: $3,200 per filer and per dependent, phased down by federal AGI — single and separate: $1,600 above $100,000, $800 above $125,000, none above $150,000; joint and head of household: $1,600 above $150,000, $800 above $175,000, none above $200,000. The tiers are keyed on federal AGI, which equals Maryland AGI for a sole proprietor with no Maryland additions or subtractions. Head of household uses schedule II (the joint schedule). 2026: rates and exemptions are unchanged (Comptroller's 2026 withholding memo). The standard deduction is indexed from 2026; the Comptroller has published $3,400 for the single basis but no joint figure ($6,800 or $6,850 depending on the rounding of the cost-of-living factor), so no 2026 file is issued yet and the site falls back to 2025 with the on-page note. Re-read once the 2026 Form 502 instructions appear. Not modeled: the local income tax (2.25%–3.30% by county on the same taxable income — larger than most people expect), the 2% surtax on net capital gains when federal AGI exceeds $350,000 (Form 502CG), and the itemized-deduction phase-out above $200,000. State credits (2026-09-08, two independent reads, then an adversarial recomputation of Worksheets 18A and 21A that corrected the first modeling): a filer with a qualifying child, or a married filer, takes 50% of the federal earned income credit against the tax (line 22) — and, only when that wipes the tax out, the excess of 45% of the federal credit over the tax as a refund (line 44). The net effect is the larger of 50% nonrefundable and 45% refundable, which the engine models as a choice between the two; the two are never added. Unmarried filers with no qualifying child instead get 100% of the federal credit, refundable, with the federal age rule waived (the calculator still needs the childless flag, which assumes ages 25–64). The child tax credit is $500 per child under 6, refundable, reduced by $50 per child for every $1,000 or part of federal AGI over $15,000 (gone from $24,001). Not modeled: the local earned income credit (it offsets the county tax, which is not modeled), the poverty level credit (5% of earned income for filers under the poverty guideline whose tax exceeds half the federal credit), and the child credit's extension to children 6–16 with a disability. 2026: the rates are permanent statute; H.B. 542 (childless expansion) was not enacted.
Michigan 2025	verified	2026-09-08	Michigan Department of Treasury : 2025 MI-1040 Instruction Book (rate p.3 and line 17; exemption $5,800 line 9a; Schedule 1 line 2 add-back of the federal self-employment tax deduction, p.11) MCL 206.51 (4.25% rate), MCL 206.30(1)(b) (add back taxes on or measured by income deducted in arriving at AGI), MCL 206.30 (exemption, indexed) Michigan Department of Treasury : 2025 MI-1040 lines 28a–28b: Michigan earned income tax credit of 30% of the federal credit, refundable; MCL 206.272(1)(d) (30% for tax years after 2022, no sunset) Verification: Two independent primary-source reads on 2026-09-05 (state 2025 form instructions / rate schedules, statute or enacted 2025 legislation), reconciled; every difference from the draft corrected and logged in notes. State credit added 2026-09-08 after two independent reads of the MI-1040 instructions and MCL 206.272. Notes 2026-09-05 audit: rate and $5,800 exemption confirmed. Corrected: Michigan requires the federal deduction for half of self-employment tax to be added back (Schedule 1, line 2), so allowsHalfSeDeduction is false. Other federal adjustments such as self-employed health insurance are not added back; when those inputs are added to the engine, Michigan must apply them. Not modeled: the homestead property tax credit and the age-based standard deductions for taxpayers born before 1953. State credit (2026-09-08, two independent reads reconciled): the Michigan earned income tax credit is 30% of the federal credit, refundable. Michigan has no child credit. 2026-09-08: conformsToFederalAdjustments set: the MI-1040 starts from federal AGI and Schedule 1 adds back only the deduction for self-employment tax, not the retirement-plan or self-employed health insurance deductions (2025 MI-1040 Instruction Book, Schedule 1 additions). Read once; confirm against Schedule 1 line list at the next audit.
Minnesota 2025	verified	2026-09-08	Minnesota Department of Revenue : 2025 Form M1 instructions (updated 2025-12-05): rate schedules p.39 (5.35% / 6.8% / 7.85% / 9.85% with the 2025 thresholds by filing status), tax table row 50,000–50,100 ($2,931 single / $2,713 joint / $3,058 separate / $2,822 head of household), standard deduction line 4 and Worksheet A/B (high-income limitation), dependent exemption line 5 and its phase-out worksheet, line 1 = federal AGI Minnesota Department of Revenue : Tax Year 2025 Inflation-Adjusted Amounts; income tax rates page; Minn. Stat. §290.06 subd. 2c (rates), §290.0123 (standard deduction), §290.0121 (dependent exemption) Minnesota Department of Revenue : 2025 Schedule M1CWFC (Minnesota child and working family credits): working family credit of 4% of the first $9,480 of earned income plus $1,000 / $2,270 / $2,710 for one / two / three or more qualifying older children, child tax credit of $1,750 per qualifying child under 18, the two added and reduced by 12% of the greater of earned income and federal AGI over $37,910 joint / $31,950 other (9% when only older children); refundable via Schedule M1REF; earned income for the self-employed from federal EIC Worksheet B (net profit less the deductible half of SE tax); Minn. Stat. §290.0661 and §290.0671 Minnesota Department of Revenue : Tax Year 2026 Inflation-Adjusted Amounts: child tax credit $1,800, working family credit on the first $9,690 of earned income (older-child add-ons $1,020 / $2,330 / $2,770), phase-out thresholds $38,770 joint / $32,680 other; the enacted 2026 omnibus (Ch. 128) leaves both credits unchanged Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the M1 instructions and the Department's inflation-adjusted-amounts documents (the second reader also read Minn. Stat. §290.0121 and §290.0123), reconciled with no differences, then attacked by a third reader who recomputed five returns by hand and matched the engine to the cent. The rate-schedule bases and the $50,000 tax-table row for all four statuses are reproduced in the test suite; the standard-deduction limitation and dependent phase-out worksheets are reproduced on worked cases. State credits added 2026-09-08 after two independent reads of Schedule M1CWFC and the statute. Notes 2026-09-07 audit: brackets, standard deduction, dependent exemption and both phase-out rules confirmed by both readers. A web-search summary offered 2024 figures as 2026 — the primary documents settle it. Minnesota starts from federal AGI (M1 line 1), so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI and there is no Minnesota line for it. Standard deduction limitation (Worksheet A): the deduction is reduced by the lesser of 80% of it and 3% of AGI between the first and second thresholds plus 10% of AGI above the second; from $1,083,150 of AGI (2025; $1,107,750 in 2026) Worksheet B applies the flat 80% cut, which the formula already yields. Dependent exemption: reduced by 2 percentage points for every $2,500 ($1,250 separate) or part of AGI over the threshold, and gone once the excess passes $122,500 ($61,250 separate). Applies to every dependent, not only children. State credits (2026-09-08, two independent reads reconciled): the working family credit (4% of the first $9,480 of earned income in 2025) and the child tax credit ($1,750 per qualifying child under 18) are added and phased out together at 12% of the greater of earned income and federal AGI over the threshold, and are refundable — a joint family at $50,000 with two children gets about $2,430. The calculator counts qualifying children under 17 for the under-18 credit — a 17-year-old's credit is missed — and does not model the add-on for older qualifying children (18 and over) or the 9% rate that applies when a filer has only older children; the childless working family credit applies to filers aged 19–64, which the calculator assumes. The advance-payment option changes only the timing of the child tax credit; the annual amount is the same. Married filing separately cannot claim either credit (the form's exception for spouses living apart is not modeled). The form rounds each line to whole dollars; the engine does not.
Minnesota 2026	verified	2026-09-08	Minnesota Department of Revenue : Tax Year 2026 Inflation-Adjusted Amounts (2025-12-01): 2026 brackets, standard deduction $15,300 / $30,600 / $23,000, dependent exemption $5,300, limitation thresholds $244,400 / $337,800 ($122,200 / $168,900 separate) and phase-out thresholds; Department press release 2025-12-16 and income tax rates page (2026-01-09) with the same figures Minnesota Department of Revenue : 2025 Form M1 instructions for the unchanged mechanics (Worksheet A/B, dependent phase-out steps); Laws 2026 ch.128 art.1 §24 re-enacting §290.06 subd. 2c with unchanged rates Minnesota Department of Revenue : 2025 Schedule M1CWFC (Minnesota child and working family credits): working family credit of 4% of the first $9,480 of earned income plus $1,000 / $2,270 / $2,710 for one / two / three or more qualifying older children, child tax credit of $1,750 per qualifying child under 18, the two added and reduced by 12% of the greater of earned income and federal AGI over $37,910 joint / $31,950 other (9% when only older children); refundable via Schedule M1REF; earned income for the self-employed from federal EIC Worksheet B (net profit less the deductible half of SE tax); Minn. Stat. §290.0661 and §290.0671 Minnesota Department of Revenue : Tax Year 2026 Inflation-Adjusted Amounts: child tax credit $1,800, working family credit on the first $9,690 of earned income (older-child add-ons $1,020 / $2,330 / $2,770), phase-out thresholds $38,770 joint / $32,680 other; the enacted 2026 omnibus (Ch. 128) leaves both credits unchanged Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the M1 instructions and the Department's inflation-adjusted-amounts documents (the second reader also read Minn. Stat. §290.0121 and §290.0123), reconciled with no differences, then attacked by a third reader who recomputed five returns by hand and matched the engine to the cent. The rate-schedule bases and the $50,000 tax-table row for all four statuses are reproduced in the test suite; the standard-deduction limitation and dependent phase-out worksheets are reproduced on worked cases. The 2026 Form M1 instructions are not yet published; every 2026 figure comes from the Department's inflation-adjustment publication. State credits added 2026-09-08 after two independent reads of the Department's 2026 inflation-adjusted amounts and Schedule M1CWFC. Notes 2026-09-07 audit: all indexed 2026 amounts confirmed from three Department publications; mechanics unchanged. A web-search summary offered 2024 figures as 2026 — the primary documents settle it. Minnesota starts from federal AGI (M1 line 1), so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI and there is no Minnesota line for it. Standard deduction limitation (Worksheet A): the deduction is reduced by the lesser of 80% of it and 3% of AGI between the first and second thresholds plus 10% of AGI above the second; from $1,083,150 of AGI (2025; $1,107,750 in 2026) Worksheet B applies the flat 80% cut, which the formula already yields. Dependent exemption: reduced by 2 percentage points for every $2,500 ($1,250 separate) or part of AGI over the threshold, and gone once the excess passes $122,500 ($61,250 separate). Applies to every dependent, not only children. State credits (2026-09-08, two independent reads reconciled): the working family credit (4% of the first $9,480 of earned income in 2025) and the child tax credit ($1,750 per qualifying child under 18) are added and phased out together at 12% of the greater of earned income and federal AGI over the threshold, and are refundable — a joint family at $50,000 with two children gets about $2,430. The calculator counts qualifying children under 17 for the under-18 credit — a 17-year-old's credit is missed — and does not model the add-on for older qualifying children (18 and over) or the 9% rate that applies when a filer has only older children; the childless working family credit applies to filers aged 19–64, which the calculator assumes. The advance-payment option changes only the timing of the child tax credit; the annual amount is the same. Married filing separately cannot claim either credit (the form's exception for spouses living apart is not modeled). The form rounds each line to whole dollars; the engine does not.
Missouri 2025	verified	2026-09-08	Missouri Department of Revenue : 2025 Form MO-1040 instructions and tax rate chart (0% to $1,313, then 2%–4.5% in $1,313 steps, $256 plus 4.7% over $9,191; examples: taxable $3,090 → $38, $12,000 → $388), federal income tax deduction worksheet (lines 9–13: 35% / 25% / 15% / 5% / 0% by Missouri AGI, caps $5,000 / $10,000), line 15 head-of-household exemption $1,400, standard deduction equal to federal Missouri Department of Revenue : 2025 Form MO-A instructions, Part 1 line 17: business income deduction of 20% of Schedule C / E Part II / F net profit (RSMo 143.022) RSMo 143.011 (rates and the SB 3 of 2022 step-downs), 143.022 (business income deduction, 20% maximum), 143.171 (federal income tax deduction table and caps), 143.151 / 143.161 (exemptions conditioned on the federal §151 amount, currently zero) Missouri Department of Revenue : 2025 Form MO-WFTC and MO-1040 instructions line 44: working family tax credit of 20% of the federal earned income credit (Form 1040 line 27a), nonrefundable, no carryforward, limited to the tax after all other credits; RSMo §143.177 (20% for tax years 2024 and after, the statutory maximum); DOR FAQ Verification: Two independent reads on 2026-09-07 of the Department's forms and instructions and the statute (the second reader blind to the first), reconciled; the only difference was the description of the head-of-household exemption, settled from the form line; a third reader then attacked the file, confirmed the form's order of operations (business income deduction before the federal-tax percentage tier) and matched five hand computations across both years within the chart's whole-dollar rounding. The Department's printed chart examples are reproduced in the test suite within $1 (the chart rounds its base amounts to whole dollars). State credit added 2026-09-08 after two independent reads of Form MO-WFTC and the statute. Notes 2026-09-07 audit: the 2025 chart, the 20% business income deduction and the federal tax deduction tiers confirmed by both readers. Contrary to the research brief's premise, the $1,200 dependent deduction and the personal exemption are not available: RSMo 143.151 and 143.161 tie them to the federal §151 amount, which is zero, and the return has no line for them. The only exemption is the $1,400 head-of-household / qualifying surviving spouse amount (line 15). Missouri starts from federal AGI, so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI. Instead RSMo 143.022 lets a sole proprietor subtract 20% of positive business income (MO-A Part 1 line 17); the engine subtracts it from AGI before the federal-tax-deduction tier lookup, which the form keys on Missouri AGI after that subtraction. Federal income tax deduction (MO-1040 lines 9–13, RSMo 143.171): federal income tax after credits (excluding self-employment tax and less the earned income credit) × 35% (Missouri AGI up to $25,000), 25% (to $50,000), 15% (to $100,000), 5% (to $125,000), 0% above; capped at $5,000 ($10,000 on a combined return). The form subtracts the earned income credit and the refundable American opportunity credit from federal tax before the percentage; the engine subtracts the refundable credits it models (EITC and the additional child tax credit — the latter can only be positive when the federal tax after credits is already zero, so the result is the same). Standard deduction equals the federal amount (RSMo 143.131). Joint filers compute tax on a combined return with each spouse's income taxed separately on the chart; for a single-earner couple the engine's single pass is exact, for two earners it overstates the tax by up to the value of the low brackets for the second spouse (about $176); the calculator has no spouse-income input. Not modeled: the Kansas City and St. Louis 1% earnings taxes (they do apply to self-employment net profit), the 100% capital-gain subtraction from 2025, the $1,200 filing threshold. State credit (2026-09-08, two independent reads reconciled): the working family tax credit is 20% of the federal earned income credit, nonrefundable and taken last, for residents filing single, head of household, qualifying surviving spouse or a combined return; married filing separately and dependents are excluded. Its investment-income cap ($4,400) follows the 2021 federal law rather than the current cap, which the calculator ignores (no investment income input). Unchanged for 2026. 2026-09-15: the capital-gain subtraction noted above is RSMo §143.121.3(14)(a), read directly: "For all tax years beginning on or after January 1, 2025, one hundred percent of all income reported as a capital gain for federal income tax purposes by an individual subject to tax pursuant to section 143.011". Paragraph (14)(b) extends it to entities under §143.071 only once the top rate reaches a statutory trigger, and §143.121.3(15) adds gain on the sale or exchange of specie (§408.010) for tax years beginning on or after 1 January 2026. Missouri effectively does not tax individual capital gains from 2025. This calculator takes no capital-gain input, so no figure it reports is affected.
Missouri 2026	verified	2026-09-08	Missouri Department of Revenue : 2026 Form MO-1040ES instructions: 2026 tax rate chart (0% to $1,348, then $1,348 steps, $263 plus 4.7% over $9,436; examples: taxable $4,000 → $60, $12,300 → $398), standard deduction $16,100 / $32,200 / $24,150 / $16,100 Missouri Department of Revenue : 2026 employer withholding formula (same chart and top rate; the SB 3 revenue trigger did not lower the 2026 rate), and the Department's 2026 legislative-changes summary (no individual rate or deduction changes) RSMo 143.011, 143.022, 143.171 (unchanged for 2026); 2025 Form MO-A line 17 and MO-1040 lines 9–15 for the deduction mechanics, which are not indexed Missouri Department of Revenue : 2025 Form MO-WFTC and MO-1040 instructions line 44: working family tax credit of 20% of the federal earned income credit (Form 1040 line 27a), nonrefundable, no carryforward, limited to the tax after all other credits; RSMo §143.177 (20% for tax years 2024 and after, the statutory maximum); DOR FAQ Verification: Two independent reads on 2026-09-07 of the Department's forms and instructions and the statute (the second reader blind to the first), reconciled; the only difference was the description of the head-of-household exemption, settled from the form line; a third reader then attacked the file, confirmed the form's order of operations (business income deduction before the federal-tax percentage tier) and matched five hand computations across both years within the chart's whole-dollar rounding. The Department's printed chart examples are reproduced in the test suite within $1 (the chart rounds its base amounts to whole dollars). State credit added 2026-09-08 after two independent reads of Form MO-WFTC, the statute and the DOR FAQ ('20% for tax year 2024 and forward'). Notes 2026-09-07 audit: the 2026 chart (indexed steps, top rate still 4.7% because the SB 3 revenue trigger did not fire) confirmed from the 2026 MO-1040ES and the withholding formula; deduction mechanics unchanged. Contrary to the research brief's premise, the $1,200 dependent deduction and the personal exemption are not available: RSMo 143.151 and 143.161 tie them to the federal §151 amount, which is zero, and the return has no line for them. The only exemption is the $1,400 head-of-household / qualifying surviving spouse amount (line 15). Missouri starts from federal AGI, so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI. Instead RSMo 143.022 lets a sole proprietor subtract 20% of positive business income (MO-A Part 1 line 17); the engine subtracts it from AGI before the federal-tax-deduction tier lookup, which the form keys on Missouri AGI after that subtraction. Federal income tax deduction (MO-1040 lines 9–13, RSMo 143.171): federal income tax after credits (excluding self-employment tax and less the earned income credit) × 35% (Missouri AGI up to $25,000), 25% (to $50,000), 15% (to $100,000), 5% (to $125,000), 0% above; capped at $5,000 ($10,000 on a combined return). The form subtracts the earned income credit and the refundable American opportunity credit from federal tax before the percentage; the engine subtracts the refundable credits it models (EITC and the additional child tax credit — the latter can only be positive when the federal tax after credits is already zero, so the result is the same). Standard deduction equals the federal amount (RSMo 143.131). Joint filers compute tax on a combined return with each spouse's income taxed separately on the chart; for a single-earner couple the engine's single pass is exact, for two earners it overstates the tax by up to the value of the low brackets for the second spouse (about $180); the calculator has no spouse-income input. Not modeled: the Kansas City and St. Louis 1% earnings taxes (they do apply to self-employment net profit), the 100% capital-gain subtraction from 2025, the $1,200 filing threshold. State credit (2026-09-08, two independent reads reconciled): the working family tax credit is 20% of the federal earned income credit, nonrefundable and taken last, for residents filing single, head of household, qualifying surviving spouse or a combined return; married filing separately and dependents are excluded. Its investment-income cap ($4,400) follows the 2021 federal law rather than the current cap, which the calculator ignores (no investment income input). Unchanged for 2026. 2026-09-15: the capital-gain subtraction noted above is RSMo §143.121.3(14)(a), read directly: "For all tax years beginning on or after January 1, 2025, one hundred percent of all income reported as a capital gain for federal income tax purposes by an individual subject to tax pursuant to section 143.011". Paragraph (14)(b) extends it to entities under §143.071 only once the top rate reaches a statutory trigger, and §143.121.3(15) adds gain on the sale or exchange of specie (§408.010) for tax years beginning on or after 1 January 2026. Missouri effectively does not tax individual capital gains from 2025. This calculator takes no capital-gain input, so no figure it reports is affected.
North Carolina 2025	verified	2026-09-08	North Carolina Department of Revenue : 2025 Form D-401 instructions (rate p.5, standard deduction line 11, child deduction table p.13, line 6 = federal AGI) N.C.G.S. §105-153.7 (4.25% for 2025, 3.99% for taxable years after 2025), §105-153.5(a)(1) (standard deduction), §105-153.5(a1) (child deduction) North Carolina Department of Revenue : 2025 Form D-400 and D-400TC: no earned income or child credit; the child deduction on line 10 is already modeled Verification: Two independent primary-source reads on 2026-09-05 (state 2025 form instructions / rate schedules, statute or enacted 2025 legislation), reconciled; every difference from the draft corrected and logged in notes. State credits reviewed 2026-09-08 by two independent readers of D-400 and D-400TC: none exist. Notes 2026-09-05 audit: rate, standard deductions and child-deduction amounts confirmed; every AGI tier boundary in the draft was exactly double the statutory figure and has been corrected (steps of $10,000 single/MFS, $15,000 HoH, $20,000 joint). The deduction applies only to children who qualify for the federal child tax credit; other dependents get nothing. The rate falls to 3.99% for 2026; a 2026 file is needed before the fallback is acceptable. North Carolina has no state EITC or child credit; nothing further is missing for a typical sole proprietor. State credits (2026-09-08, two independent reads reconciled): North Carolina has no earned income or child credit; its child deduction is modeled.
North Carolina 2026	verified	2026-09-08	North Carolina Department of Revenue : Tax Rate Schedules page: 'For Taxable Years after 2025, the North Carolina individual income tax rate is 3.99% (0.0399)'; further trigger-based cuts apply to 2027 and later only N.C.G.S. §105-153.7 (rate table : 2025 4.25%, after 2025 3.99%; trigger mechanism for later years, S.L. 2023-134 s.42.1(a)), §105-153.5(a)(1) (standard deduction $12,750 / $25,500 / $19,125, unchanged through S.L. 2026-11) and §105-153.5(a1) (child deduction table, unchanged), read at ncleg.gov on 2026-09-07 North Carolina Department of Revenue : 2025 Form D-400 and D-400TC: no earned income or child credit; the child deduction on line 10 is already modeled Verification: Two independent primary-source reads on 2026-09-07 (NCDOR rate schedule page; the enacted statute text at ncleg.gov including its session-law history), reconciled. The 2026 Form D-401 instructions are not yet published; re-read the rate, standard deduction and child deduction table against them when they appear. State credits reviewed 2026-09-08 by two independent readers of D-400 and D-400TC: none exist. Notes 2026-09-07: the only change from 2025 is the rate, 4.25% → 3.99%, the last scheduled step in S.L. 2023-134. Rate cuts for 2027 and later depend on General Fund revenue triggers and are not assumed. Standard deduction and child-deduction tiers are unchanged from 2025; the statute's session-law history runs through S.L. 2026-11 with the same amounts. The deduction applies only to children who qualify for the federal child tax credit; other dependents get nothing. North Carolina has no state EITC or child credit; nothing further is missing for a typical sole proprietor. State credits (2026-09-08, two independent reads reconciled): North Carolina has no earned income or child credit; its child deduction is modeled.
New Jersey 2025	verified	2026-09-08	New Jersey Division of Taxation : 2025 Form NJ-1040 instructions, tax rate schedules N.J.S.A. 54A:2-1 (rates), 54A:3-1 (personal and dependent exemptions) New Jersey Division of Taxation : 2025 Form NJ-1040 and instructions: line 58 New Jersey earned income tax credit (40% of the federal credit, refundable; flat $260 for childless filers aged 18 or over who meet every federal rule except age; married filing separately only with a qualifying child and living apart), line 65 New Jersey child tax credit (per child aged 5 or under, by New Jersey taxable income: $1,000 up to $30,000, $800 to $40,000, $600 to $50,000, $400 to $60,000, $200 to $80,000; refundable; not for married filing separately); N.J.S.A. 54A:4-7 and 54A:4-17.1 P.L.2026, c.26 (S-4531, approved 2026-06-30) : the child tax credit table rises to $1,250 / $1,000 / $750 / $500 / $250 for tax years 2026–2028 (read on pub.njleg.gov); not yet reflected here because the 2026 New Jersey data file does not exist — the 2026 estimate uses the 2025 table New Jersey Division of Taxation : Income Tax: Business Income (njit11): sole proprietors deduct qualified contributions to a self-employed 401(k) plan in computing net profit; contributions above the federal limits are not deductible New Jersey Division of Taxation : Income Tax: Deductions (njit13) and 2025 NJ-1040 instructions, Worksheet F: the self-employed health insurance deduction is added on line 5 after the 2% medical-expense floor; IRA and Keogh contributions are not deductible Verification: Two independent primary-source reads on 2026-09-05 (state 2025 form instructions / rate schedules, statute or enacted 2025 legislation), reconciled; every difference from the draft corrected and logged in notes. State credits added 2026-09-08 after two independent reads of the NJ-1040 instructions and the 2026 chapter law. Notes 2026-09-05 audit: brackets, exemptions and the no-half-SE rule confirmed against the 2025 NJ-1040 instructions (Schedule NJ-BUS-1 Part I allows no adjustment for self-employment tax). Added the filing threshold: no tax when gross income is $10,000 or less ($20,000 joint or head of household) — a cliff measured on gross income before exemptions. New Jersey does allow the self-employed health insurance deduction and self-employed 401(k) contributions; when those inputs exist in the engine, New Jersey must apply them (SEP and IRA contributions are not deductible). Not modeled: the property tax deduction or credit and the health-coverage shared responsibility payment. State credits (2026-09-08, two independent reads reconciled): the New Jersey earned income tax credit is 40% of the federal credit, refundable; childless filers 18 and over get a flat $260 in 2025, which the calculator approximates as 40% of the federal childless credit (the same figure at the federal maximum, and only when the childless flag is set). The child tax credit is per child aged 5 or under, stepped by New Jersey taxable income and refundable; married filing separately cannot claim either credit. The calculator counts the 'children under 6' input. 2026: P.L.2026, c.26 raises the child tax credit table by 25% for 2026–2028 ($1,250 at the lowest band); a 2026 New Jersey file is needed to carry it — until then the 2026 estimate shows the 2025 amounts and says so. 2026-09-17 correction: the self-employed health insurance premium and self-employed 401(k) contributions were refused along with everything else the engine's single conformity switch covers, although this file's own note said New Jersey allows both. The Division of Taxation's income-tax pages state it: Schedule NJ-BUS-1 net profit is after "qualified contributions to a self-employed 401(k) Plan" (contributions above the federal limits are not deductible), and the self-employed health insurance deduction is line 5 of the NJ-1040 medical expenses Worksheet F, outside the 2% floor; SEP-IRA, Keogh and IRA contributions remain non-deductible. adjustmentsAllowed now says so. A single filer with $100,000 of profit and $10,000 of premiums was charged $4,180.05 instead of $3,543.05; with a $20,000 solo 401(k) contribution, $4,180.05 instead of $2,906.05; a SEP-IRA contribution was, correctly, still refused. The premium is deducted after gross income, so it does not count towards the $10,000 / $20,000 no-tax threshold; the 401(k) contribution, inside net profit, does. Found by an external review on 2026-09-17.
New Jersey 2026	verified	2026-09-08	New Jersey Division of Taxation : 2025 Form NJ-1040 instructions, tax rate schedules N.J.S.A. 54A:2-1 (rates), 54A:3-1 (personal and dependent exemptions) New Jersey Division of Taxation : 2025 Form NJ-1040 and instructions: line 58 New Jersey earned income tax credit (40% of the federal credit, refundable; flat $260 for childless filers aged 18 or over who meet every federal rule except age; married filing separately only with a qualifying child and living apart), line 65 New Jersey child tax credit (per child aged 5 or under, by New Jersey taxable income: $1,000 up to $30,000, $800 to $40,000, $600 to $50,000, $400 to $60,000, $200 to $80,000; refundable; not for married filing separately); N.J.S.A. 54A:4-7 and 54A:4-17.1 P.L.2026, c.26 (S-4531, approved 2026-06-30), read on pub.njleg.gov : New Jersey child tax credit of $1,250 / $1,000 / $750 / $500 / $250 by the same New Jersey taxable income bands for tax years 2026–2028, reverting in 2029 New Jersey's rates, brackets, exemptions and the earned income tax credit share are unindexed statute (N.J.S.A. 54A:2-1, 54A:3-1, 54A:4-7) and unchanged by any 2026 enactment found in the P.L.2026 chapter list; the 2025 NJ-1040 figures therefore carry into 2026 New Jersey Division of Taxation : Income Tax: Business Income (njit11): sole proprietors deduct qualified contributions to a self-employed 401(k) plan in computing net profit; contributions above the federal limits are not deductible New Jersey Division of Taxation : Income Tax: Deductions (njit13) and 2025 NJ-1040 instructions, Worksheet F: the self-employed health insurance deduction is added on line 5 after the 2% medical-expense floor; IRA and Keogh contributions are not deductible Verification: Two independent primary-source reads on 2026-09-05 (state 2025 form instructions / rate schedules, statute or enacted 2025 legislation), reconciled; every difference from the draft corrected and logged in notes. State credits added 2026-09-08 after two independent reads of the NJ-1040 instructions and the 2026 chapter law. The 2026 file carries the 2025 figures (unindexed statute) with the child tax credit table from the enacted P.L.2026, c.26, read by both readers. Notes 2026-09-05 audit: brackets, exemptions and the no-half-SE rule confirmed against the 2025 NJ-1040 instructions (Schedule NJ-BUS-1 Part I allows no adjustment for self-employment tax). Added the filing threshold: no tax when gross income is $10,000 or less ($20,000 joint or head of household) — a cliff measured on gross income before exemptions. New Jersey does allow the self-employed health insurance deduction and self-employed 401(k) contributions; when those inputs exist in the engine, New Jersey must apply them (SEP and IRA contributions are not deductible). Not modeled: the property tax deduction or credit and the health-coverage shared responsibility payment. State credits (2026-09-08, two independent reads reconciled): the New Jersey earned income tax credit is 40% of the federal credit, refundable; childless filers 18 and over get a flat $260 in 2025, which the calculator approximates as 40% of the federal childless credit (the same figure at the federal maximum, and only when the childless flag is set). The child tax credit is per child aged 5 or under, stepped by New Jersey taxable income and refundable; married filing separately cannot claim either credit. The calculator counts the 'children under 6' input. 2026 file (2026-09-08): identical to 2025 except the child tax credit table, raised 25% by P.L.2026, c.26 for 2026–2028. New Jersey does not index its brackets or exemptions; re-read against the 2026 NJ-1040 instructions when published. 2026-09-17 correction: the self-employed health insurance premium and self-employed 401(k) contributions were refused along with everything else the engine's single conformity switch covers, although this file's own note said New Jersey allows both. The Division of Taxation's income-tax pages state it: Schedule NJ-BUS-1 net profit is after "qualified contributions to a self-employed 401(k) Plan" (contributions above the federal limits are not deductible), and the self-employed health insurance deduction is line 5 of the NJ-1040 medical expenses Worksheet F, outside the 2% floor; SEP-IRA, Keogh and IRA contributions remain non-deductible. adjustmentsAllowed now says so. A single filer with $100,000 of profit and $10,000 of premiums was charged $4,180.05 instead of $3,543.05; with a $20,000 solo 401(k) contribution, $4,180.05 instead of $2,906.05; a SEP-IRA contribution was, correctly, still refused. The premium is deducted after gross income, so it does not count towards the $10,000 / $20,000 no-tax threshold; the 401(k) contribution, inside net profit, does. Found by an external review on 2026-09-17.
New York 2025	verified	2026-09-08	New York State Department of Taxation and Finance : 2025 Form IT-201 instructions: tax rate schedule, standard deduction (line 34), dependent exemption (line 36), and tax computation worksheets 1–16 for New York AGI over $107,650 N.Y. Tax Law §601 (rates and tax benefit recapture, as amended by Ch. 59 of the Laws of 2025 Part A), §614 (standard deduction), §616 (dependent exemption) New York State Department of Taxation and Finance : 2025 Form IT-215 instructions (New York State earned income credit: 30% of the federal credit as claimed, refundable for residents, reduced by the household credit actually used — lines 13–16) and Form IT-213 instructions (Empire State child credit: $1,000 per child under 4 and $330 per child aged 4–16 for 2025, reduced by 1.65% of federal AGI — rounded down to $1,000 — over $110,000 joint / $75,000 single, head of household and surviving spouse / $55,000 separate; refundable); N.Y. Tax Law §606(d) and §606(c-1)(1-a) N.Y. Tax Law §606(c-1)(1-a)(B) and the Department's Empire State child credit page (updated 2026-03-10) : $1,000 per child under 4 and $500 per child aged 4–16 for 2026 and 2027, same phase-out Verification: Two independent primary-source reads on 2026-09-05 (2025 IT-201 instructions and Tax Law §601), reconciled; the tax benefit recapture worksheets were transcribed from the same instructions on 2026-09-06 and every published recapture base and incremental benefit amount is re-derived from the rate schedule in the test suite. State credits added 2026-09-08 after two independent reads of IT-215 and IT-213. A third reader attacked the credit modeling and its IT-213 recomputation drove the single-credit form of the phase-out. Notes 2026-09-05 audit: brackets, standard deduction and $1,000 dependent exemption confirmed; 2025 rates are unchanged by the FY2026 budget (the 0.1-point cuts to the five lowest rates start in tax year 2026, with a further 0.1 in 2027). 2026-09-06: tax benefit recapture implemented from the IT-201 tax computation worksheets. Above $107,650 of New York AGI the benefit of the lower brackets is phased out over $50,000 of AGI, first to the rate of the bracket containing the first recapture threshold (5.5% joint, 6% others), then tier by tier with the published recapture base and incremental benefit amounts; above $25,000,000 all taxable income is taxed at 10.9%. Worksheet factors are rounded to four decimals as instructed. The $8,000 single standard deduction applies to filers who cannot be claimed as a dependent ($3,100 otherwise). A 2026 file is needed (rates 3.9/4.4/5.15/5.4/5.9% on the five lowest brackets; recapture amounts change with them). Not modeled: the New York City earned income credit (10–30% of the federal credit by income, city residents only), the household credit, and the 2025 one-time inflation refund (paid off 2023 returns, not a return item). State credits (2026-09-08, two independent reads, then an adversarial recomputation of IT-213 that corrected the first modeling): the New York earned income credit is 30% of the federal credit, refundable; the form reduces it by the household credit actually used (a nonrefundable credit of $20–$105 for federal AGI under about $32,000) — for families with children the two cancel in the total, so only the credit line shown is up to about $80 high; childless filers at $20,000–$28,000 are overtaxed by $20–$45. The Empire State child credit for 2025 is $1,000 per child under 4 and $330 per child aged 4–16 — modeled as one credit with a young-child bonus on the 'children under 4' input — reduced as a whole, but not below zero, by 1.65% of federal AGI over the threshold rounded down to $1,000; refundable.
New York 2026	verified	2026-09-08	N.Y. Tax Law §601(a)–(c), rate schedules 'for taxable years beginning after 2025 and before 2027' (3.9% / 4.4% / 5.15% / 5.4% / 5.9% on the five lowest brackets; 6.85%, 9.65%, 10.3%, 10.9% unchanged; thresholds unchanged), as amended by Ch. 59 of the Laws of 2025 Part A, read at nysenate.gov; §601(d-1) (tax table benefit recapture, applied with the current-year rates); §614 (standard deduction, not amended); §616 (dependent exemption) New York State Department of Taxation and Finance : Publication NYS-50-T-NYS (1/26), New York State Withholding Tax Tables and Methods: 'The 2026 New York State personal income tax rate schedules have been revised to reflect certain income tax rate reductions enacted under Chapter 59 of the Laws of 2025 (Part A)'; annual rate schedules on pp.17 and 19 use 3.9% / 4.4% / 5.15% / 5.4% / 5.9% up to $215,400 (single) and $323,200 (married) with the same thresholds as 2025 2025 Form IT-201 instructions : tax computation worksheets 1–16 (structure of the recapture; the 2026 worksheets are not yet published) New York State Department of Taxation and Finance : 2025 Form IT-215 instructions (New York State earned income credit: 30% of the federal credit as claimed, refundable for residents, reduced by the household credit actually used — lines 13–16) and Form IT-213 instructions (Empire State child credit: $1,000 per child under 4 and $330 per child aged 4–16 for 2025, reduced by 1.65% of federal AGI — rounded down to $1,000 — over $110,000 joint / $75,000 single, head of household and surviving spouse / $55,000 separate; refundable); N.Y. Tax Law §606(d) and §606(c-1)(1-a) N.Y. Tax Law §606(c-1)(1-a)(B) and the Department's Empire State child credit page (updated 2026-03-10) : $1,000 per child under 4 and $500 per child aged 4–16 for 2026 and 2027, same phase-out Verification: Two independent primary-source reads on 2026-09-07: the codified §601 schedule at nysenate.gov and the Department's January 2026 withholding publication, reconciled (every statutory dollar base is reproduced from the rates within $1 in the test suite). The recapture base and incremental amounts are derived from the 2026 schedule by the same §601(d-1) arithmetic that reproduces every published 2025 worksheet figure within $1; they must be checked against the 2026 IT-201 worksheets when published (expected January 2027). State credits added 2026-09-08 after two independent reads of IT-215, IT-213 and Tax Law §606(c-1)(1-a) as amended for 2026. A third reader attacked the credit modeling and its IT-213 recomputation drove the single-credit form of the phase-out. Notes 2026-09-07: Ch. 59 of the Laws of 2025 (Part A) cuts the five lowest rates by 0.1 point for 2026 (4% → 3.9%, 4.5% → 4.4%, 5.25% → 5.15%, 5.5% → 5.4%, 6% → 5.9%) and by a further 0.1 point for 2027 and later. Bracket thresholds, the 6.85% and higher rates, the $107,650 recapture start and the $50,000 window are unchanged. Tax benefit recapture re-derived for 2026: the first tier now phases the tax up to a flat 5.9% (5.4% joint) instead of 6% (5.5%); for single filers the tier above $215,400 keeps a $568 base but its incremental benefit rises to $2,046 because the gap between 5.9% and 6.85% is wider than the 2025 gap between 6% and 6.85%. Above $25,000,000 of AGI everything is still taxed at 10.9%. Standard deduction ($8,000 / $16,050 / $11,200) and the $1,000 dependent exemption are carried from 2025: §614 was not amended and the Department has published no 2026 change; confirm against the 2026 IT-201 instructions. The $8,000 single standard deduction applies to filers who cannot be claimed as a dependent ($3,100 otherwise). Not modeled: the New York City earned income credit (10–30% of the federal credit by income, city residents only), the household credit, and the 2025 one-time inflation refund (paid off 2023 returns, not a return item). State credits (2026-09-08, two independent reads, then an adversarial recomputation of IT-213 that corrected the first modeling): the New York earned income credit is 30% of the federal credit, refundable; the form reduces it by the household credit actually used (a nonrefundable credit of $20–$105 for federal AGI under about $32,000) — for families with children the two cancel in the total, so only the credit line shown is up to about $80 high; childless filers at $20,000–$28,000 are overtaxed by $20–$45. The Empire State child credit for 2026 is $1,000 per child under 4 and $500 per child aged 4–16 — modeled as one credit with a young-child bonus on the 'children under 4' input — reduced as a whole, but not below zero, by 1.65% of federal AGI over the threshold rounded down to $1,000; refundable.
Ohio 2025	verified	2026-09-08	Ohio Department of Taxation : 2025 Ohio IT 1040 booklet (rate schedule p.4/18, exemption table p.17, business income deduction p.11/27) and 2025 IT BUS schedule Ohio Rev. Code §5747.02 (rates, as amended by H.B. 96 of 2025), §5747.01(A)(28) (business income deduction), §5747.025 (personal exemption) Ohio Department of Taxation : 2025 Ohio Schedule of Credits: line 13 earned income credit (30% of the federal credit, nonrefundable, after the exemption credit and joint filing credit) and the $20 personal exemption credit for filers whose modified adjusted gross income less exemptions is under $30,000; R.C. 5747.71 and 5747.022 Verification: Two independent primary-source reads on 2026-09-05 (2025 Ohio IT 1040 booklet, IT BUS schedule, R.C. 5747.01/5747.02/5747.025), reconciled; the nonbusiness schedule was re-read on 2026-09-06 against both the booklet (p.18) and the statute text at codes.ohio.gov, and the booklet's worked example is reproduced in the test suite. State credits added 2026-09-08 after two independent reads of the 2025 Schedule of Credits. Notes 2026-09-05 audit: brackets, exemption tiers, business income deduction amounts and the flat 3% rate all match the 2025 booklet and statute. A fourth exemption tier (MAGI $750,000 and above → $0) was added, and the business income mechanics follow the IT BUS schedule: the deduction is the lesser of business income, federal AGI and $250,000; business income taxed at 3% is capped at Ohio taxable income after exemptions; only what remains goes through the brackets. Exemption tiers key off MAGI (Ohio AGI before the deduction), which for a sole proprietor equals federal AGI. 2026-09-06: the nonbusiness schedule's apparent inconsistency is in the statute itself. R.C. 5747.02(A)(3)(b) for 2025 reads '$342.00 plus 2.75% of the amount in excess of $26,050' up to $100,000 and '$2,394.32 plus 3.125% of the amount in excess of $100,000' above it; $342 + 2.75% × $73,950 = $2,375.63, so the schedule steps up by $18.695 at $100,000 (the $2,394.32 base is the unchanged 2024 figure). The booklet (p.18) prints the same lines, and its worked example ($68,050 → $1,497) confirms the $342 step. The engine reproduces the statute as written: a $342 step above $26,050 and an $18.695 step above $100,000. Only filers with nonbusiness income above $100,000 are affected. H.B. 96 sets a single 2.75% rate with a $332 step at $26,050 for 2026 and later (R.C. 5747.02(A)(3)(c)) and no second step; a 2026 file is needed once the 2026 exemption amounts are published. The $20 per-exemption credit for MAGI under $30,000, the joint filing credit, and school district income taxes are not modeled. State credits (2026-09-08, two independent reads reconciled): Ohio's earned income credit is 30% of the federal credit, nonrefundable, taken after the other credits; there is no Ohio child tax credit for 2025 or 2026 (the credit proposed in H.B. 96 was dropped). The $20 credit per exemption for filers whose modified AGI less exemptions is under $30,000 is applied before the earned income credit, as on the Schedule of Credits. Not modeled: the joint filing credit (5–20% of the tax, up to $650, for couples where each spouse has at least $500 of income) and the child and dependent care credit.
Ohio 2026	verified	2026-09-08	Ohio Rev. Code §5747.02(A)(3)(c) (single 2.75% rate above $26,050 with the $332 base for taxable years beginning in 2026 and thereafter) and §5747.025(A) (exemption tiers; no exemption at MAGI of $500,000 or more from 2026), both as amended by H.B. 96 of the 136th General Assembly, effective 2025-09-30, read at codes.ohio.gov Ohio Legislative Service Commission : H.B. 96 bill analysis, Department of Taxation section: flat 2.75% for 2026, inflation indexing of brackets and personal exemptions suspended for taxable years 2025 and 2026 (Section 757.120(A)), $500,000 MAGI limit for exemptions from 2026 Ohio Department of Taxation : 2025 Ohio IT 1040 booklet (exemption table p.17, business income deduction p.11/27) for the indexed exemption amounts that the suspension carries into 2026 Ohio Department of Taxation : 2025 Ohio Schedule of Credits: line 13 earned income credit (30% of the federal credit, nonrefundable, after the exemption credit and joint filing credit) and the $20 personal exemption credit for filers whose modified adjusted gross income less exemptions is under $30,000; R.C. 5747.71 and 5747.022 Verification: Two independent primary-source reads on 2026-09-07: the codified statute text at codes.ohio.gov and the LSC analysis of H.B. 96, reconciled with the 2025 booklet for the carried-forward exemption amounts. The 2026 IT 1040 booklet is not yet published; the file must be re-read against it (rate schedule, exemption table, IT BUS) when it appears. State credits added 2026-09-08 after two independent reads of the 2025 Schedule of Credits and R.C. 5747.71 (unchanged for 2026). Notes 2026-09-07: H.B. 96 completes the flattening. For taxable years beginning in 2026 the nonbusiness schedule is a single line — '$332.00 plus 2.75% of the amount in excess of $26,050' — so the engine keeps a $332 step at $26,050 and no second step; the 2025 file's $18.695 step at $100,000 disappears with the 3.125% bracket. Indexing: R.C. 5747.02(A)(5) and 5747.025(C) index the $26,050 threshold and the exemption amounts each August, but Section 757.120(A) of H.B. 96 suspends the adjustment for taxable years 2025 and 2026. The statutory base amounts printed in 5747.025 ($2,350 / $2,100 / $1,850) are pre-indexing figures; the indexed amounts in force since 2024 ($2,400 / $2,150 / $1,900) therefore carry into 2026 unchanged, as the 2025 booklet and the Tax Foundation's 2026 table both show. Exemption phase-out: the exemption is available only while MAGI is less than $500,000 for 2026 (it was $750,000 for 2025). Exemption tiers key off MAGI (Ohio AGI before the business income deduction), which for a sole proprietor equals federal AGI. Business income deduction unchanged: the lesser of business income, federal AGI and $250,000 ($125,000 MFS) is excluded; the excess is taxed at a flat 3% and capped at Ohio taxable income after exemptions; only what remains goes through the nonbusiness schedule. The $20 per-exemption credit for MAGI under $30,000, the joint filing credit, and school district income taxes are not modeled. State credits (2026-09-08, two independent reads reconciled): Ohio's earned income credit is 30% of the federal credit, nonrefundable, taken after the other credits; there is no Ohio child tax credit for 2025 or 2026 (the credit proposed in H.B. 96 was dropped). The $20 credit per exemption for filers whose modified AGI less exemptions is under $30,000 is applied before the earned income credit, as on the Schedule of Credits. Not modeled: the joint filing credit (5–20% of the tax, up to $650, for couples where each spouse has at least $500 of income) and the child and dependent care credit. 2026-09-15: Ohio's own 2026 estimated-tax instructions contradict the statute, and this engine follows the statute. R.C. 5747.02(A)(3)(c), as amended by H.B. 96 (effective 30 September 2025), reads "For taxable years beginning in 2026 and thereafter, $332.00 plus 2.75% of the amount in excess of $26,050" — one bracket, no step at $100,000. The Department of Taxation's 2026 Ohio Estimated Income Tax Instructions (ites-instructions-fi.pdf, last modified 4 May 2026) still print the 2025 table: "$26,050 – $100,000 $342.00 plus 2.750%" and "$100,000 – $2,394.32 plus 3.125%". On $200,000 of nonbusiness income the statute gives $5,115.63 and the worksheet $5,519.32, a difference of $403.69; on $500,000, $13,365.63 against $14,894.32, a difference of $1,528.69. Both documents were read directly and the arithmetic recomputed here. Re-check against the 2026 IT 1040 booklet when it is published (usually December).
Pennsylvania 2025	verified	2026-09-08	Pennsylvania Department of Revenue : 2025 PA-40 instructions 72 P.S. §7302 : 3.07% flat rate Pennsylvania Department of Revenue : 2025 PA-40 Schedule SP and instructions (tax forgiveness): eligibility income tables — 100% forgiven at or below $6,500 unmarried / $13,000 married (even when filing separately) plus $9,500 per dependent child, falling 10 points for each $250 or part above that to 0%; eligibility income = the positive PA income classes (a business loss counts as zero) plus listed nontaxable income; dependent = a child of any age claimed as a federal dependent; PA-40 line 21 City of Philadelphia, Department of Revenue : Net Profits Tax page (tax rates by year: 2025 residents 3.74%, non-residents 3.43%; 2024 3.75% / 3.44%) and the 2026-06-11 notice on rate changes (tax year 2026: 3.735% / 3.425%) Pennsylvania Department of Revenue : PA Personal Income Tax Guide, Deductions and Credits (read 2026-09-18): federal adjustments not allowed, including one-half of self-employment tax, the self-employed health insurance deduction and self-employed SEP, SIMPLE and qualified plans ('No provision'); the four deductions allowed (MSA, HSA, §529, §529A) Pennsylvania Department of Revenue : PA Personal Income Tax Guide, Net Income (Loss) from the Operation of a Business, Profession or Farm (read 2026-09-18): contributions by a self-employed individual to his own pension plan or welfare benefit program are not deductible nor excludable; a sole proprietor cannot deduct his own pension and profit-sharing contributions; contributions to benefit plans established for sole proprietors cannot be deducted Verification: Two independent primary-source reads on 2026-09-05 (state 2025 form instructions / rate schedules, statute or enacted 2025 legislation), reconciled; every difference from the draft corrected and logged in notes. Tax forgiveness added 2026-09-08 after two independent reads of Schedule SP and its instructions. Notes 2026-09-05 audit: 3.07% rate, absence of a standard deduction and exemptions, and the disallowance of the federal ½-SE-tax deduction confirmed against the 2025 PA-40 instructions and the PA Personal Income Tax Guide (net profits class; 'one-half of self-employment taxes — no provision'). No figures changed. Pennsylvania has no provision for SEP, solo 401(k) or IRA contributions, the self-employed health insurance deduction or the other federal above-the-line deductions; the calculator takes none of them off Pennsylvania income and says so under the result (adjustmentsAllowed). Tax forgiveness is modeled — see the state-credits note. Local earned income / net profits taxes (typically 1%; Philadelphia 3.74% for 2025, 3.735% for 2026) are outside this model. State credits (2026-09-08, two independent reads reconciled): Pennsylvania has no earned income or child credit, but tax forgiveness (Schedule SP) cancels the whole tax for a sole proprietor whose net profit plus wages is at or below $6,500 unmarried / $13,000 married plus $9,500 per dependent child, and a falling share above that (10 points per $250). The engine uses net profit and wages as eligibility income (nontaxable items such as gifts and tax-exempt interest, which raise it, are not collected), counts the qualifying children and the other dependents as dependent children (Pennsylvania counts dependent children of any age; a dependent parent would be overcounted), and treats a separate filer's own income as the joint income the form asks for. The child and dependent care credit (100% of the federal credit) is not modeled. 2026-09-17 correction: Philadelphia's resident rate was given as 3.75%, the 2024 figure. The city's net profits tax page lists 3.74% for tax year 2025 (3.43% non-resident), and its 2026-06-11 notice sets 3.735% (3.425%) for tax year 2026. The rate is outside this model and only quoted; the quote is now by year. 2026-09-18 audit: the refusal of the self-employed health insurance deduction and of SEP-IRA / solo 401(k) contributions confirmed against the Department's own texts. The PIT Guide's Deductions and Credits chapter lists both federal adjustments as 'No provision' (with one-half of self-employment tax) and names the only four deductions Pennsylvania allows (MSA, HSA, §529 and §529A contributions). The Net Income (Loss) from the Operation of a Business chapter adds that contributions by a self-employed individual to his own pension plan (IRA, Keogh or welfare benefit program) are neither deductible as a business expense nor otherwise excludable, that a sole proprietor cannot deduct his own pension or profit-sharing contributions, and that contributions to benefit plans established for sole proprietors cannot be deducted. adjustmentsAllowed now states this explicitly; the engine's behaviour is unchanged.
South Carolina 2025	verified	2026-09-08	South Carolina Department of Revenue : 2025 SC1040 and instructions (dor.sc.gov): line 1 = federal taxable income (Form 1040 line 15), addition line for the §199A qualified business income deduction, dependent exemption $4,930 (and a further $4,930 per child under six, not modeled), rate schedule 0% to $3,560, 3% less $107 to $17,830, 6% less $642 above; 2025 SC1040TT tax table rows 17,000–17,100 → $405, 30,000–30,100 → $1,161, 50,000–50,100 → $2,361 (all statuses); the 'at or above $100,000' computation 6% × income − $642 South Carolina Department of Revenue : 2025 Form I-335 and its instructions (Active Trade or Business Income Reduced Rate Computation): flat 3% rate, Worksheet 1 safe harbor (50% of pass-through income when such income is $100,000 or less), line 2b subtraction of the deductible part of self-employment tax S.C. Code §12-6-510 (rates; top rate 6% for 2025 after the scheduled reduction), §12-6-545 (active trade or business income election), §12-6-1140 (dependent exemption) South Carolina Department of Revenue : Revenue Ruling #08-2 (active trade or business income): the safe harbor's $100,000 test and the 50% share both use pass-through income after its deductions, including one-half of self-employment tax (Q10, Q16); $100,000 is the safe-harbor eligibility line, not a cap on the election South Carolina Department of Revenue : Form TC-60 (earned income tax credit: 125% of the federal credit for full-year residents, nonrefundable, entered on SC1040TC code 060 → SC1040 line 13; agency example $1,190 × 125% = $1,488); S.C. Code §12-6-3632 Act 110 of 2026 (H.4216) §7 : the credit is capped at $200 for tax years beginning after 2025 Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the SC1040 instructions, the SC1040TT table, Form I-335 and the statute, reconciled with no differences (the February 2025 SC1040ES had printed 6.2%; both readers confirmed the 6% cut from the June 2025 table and I-335). Tax-table rows and the I-335 safe harbor are reproduced in the test suite. A third reader then attacked the file, fetched Revenue Ruling #08-2 (which settled the safe-harbor base as pass-through income after the half-SE deduction) and matched three hand computations within $2. State credit added 2026-09-08 after two independent reads of Form TC-60 and the statute. Notes 2026-09-07 audit: the starting point, the QBI addback, the dependent exemption, the 2025 schedule and the I-335 mechanics confirmed by both readers. South Carolina's 2025 taxable income starts from FEDERAL taxable income (SC1040 line 1 = Form 1040 line 15), so the federal standard deduction already applies and the deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction is then added back for every filer. The state's own dependent exemption ($4,930 per dependent) is subtracted after that. The I-335 election (S.C. Code §12-6-545): a sole proprietor may have active trade or business income taxed at a flat 3% instead of the brackets. Under the safe harbor (Revenue Ruling #08-2), when pass-through income — net profit after its deductions, including the deductible half of self-employment tax — is $100,000 or less, half of it is treated as personal-service compensation and the other half is the active trade or business income taxed at 3%. Above $100,000 the election is still available but the filer must document the personal-services split, which the calculator does not attempt; it applies the election only within the safe harbor and only when it lowers the tax (never at taxable incomes still inside the 3% bracket). The rate schedule's dollar constants ($107, $642) are the cumulative bracket arithmetic rounded to whole dollars; the engine computes the brackets exactly, which matches the table within its $0.30 rounding. State credit (2026-09-08, two independent reads reconciled): 125% of the federal earned income credit, nonrefundable, for full-year residents — it usually wipes out the tax of a family with children under about $50,000 of income. Not modeled: the two-wage-earner credit (needs spouse income) and the child and dependent care credit. 2026-09-15: not modeled — S.C. Code §12-6-1150(A), the 44% net capital gain deduction: "Individuals, estates, and trusts are allowed a deduction from South Carolina taxable income equal to forty-four percent of net capital gain recognized in this State during a taxable year", with net capital gain "as defined in Internal Revenue Code, Section 1222 and related sections" (§12-6-1150(B)(2)). Act 110 of 2026 does not amend it, so it survives the move to a federal-AGI base. This calculator takes no capital-gain input, so the omission changes no figure it reports; it would have to be modeled before any capital gain enters the base. Note that SC1040 line i describes it more loosely as "44% of net capital gains held for more than one year", which omits the netting against short-term losses that §1222(11) requires.
South Carolina 2026	verified	2026-09-08	Act 110 of 2026 (H.4216, signed 2026-03-30) : S.C. Code §12-6-510(C) two-bracket schedule for tax years from 2026 (1.99% below $30,000; 5.21% less $966 at or above, all filing statuses, indexed), §12-6-1140(15) South Carolina individual adjustment deduction (SCIAD: $15,000 single and separate, $22,500 head of household, $30,000 joint and surviving spouse, phased out over $40,001–$94,999 / $60,001–$142,499 / $80,001–$189,999 of federal AGI, reductions rounded down to $10), and the new starting point at federal AGI with the federal standard, itemized, QBI, senior, tip and overtime deductions disallowed South Carolina Department of Revenue : Information Letter #26-20 (2026-08-31) and the Department's 'Information about H.4216' page: the 2026 brackets, the SCIAD amounts and phase-out windows, the federal-AGI starting point, the $200 EITC cap. (The 2026 SC1040ES, revised 2025-10-13, predates Act 110 and prints the old schedule.) S.C. Code §12-6-545 (I-335 election, untouched by Act 110) and §12-6-1140 (dependent exemption, untouched; the 2026 indexed amount is not yet published : the 2025 $4,930 is carried provisionally) South Carolina Department of Revenue : Revenue Ruling #08-2 (active trade or business income): the safe harbor's $100,000 test and the 50% share both use pass-through income after its deductions, including one-half of self-employment tax (Q10, Q16); $100,000 is the safe-harbor eligibility line, not a cap on the election South Carolina Department of Revenue : Form TC-60 (earned income tax credit: 125% of the federal credit for full-year residents, nonrefundable, entered on SC1040TC code 060 → SC1040 line 13; agency example $1,190 × 125% = $1,488); S.C. Code §12-6-3632 Act 110 of 2026 (H.4216) §7 : the credit is capped at $200 for tax years beginning after 2025 Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the enacted Act 110 text and Information Letter #26-20, reconciled with no differences. The 2026 SC1040, its instructions, the tax table and the 2026 I-335 are not yet published; the dependent exemption amount is the 2025 figure pending the Department's 2026 indexation. Re-read every figure against the 2026 forms when they appear. A third reader then attacked the file, fetched Revenue Ruling #08-2 (which settled the safe-harbor base as pass-through income after the half-SE deduction) and matched three hand computations within $2. State credit added 2026-09-08 after two independent reads of Form TC-60 and Act 110 §7. Notes 2026-09-07: Act 110 is a structural break. From 2026 South Carolina starts from FEDERAL AGI instead of federal taxable income and disallows the federal standard, itemized and QBI deductions; in their place comes the South Carolina individual adjustment deduction, a sliding-scale standard deduction of $15,000 single / $22,500 head of household / $30,000 joint that phases out over the AGI windows above (the reduction is the maximum times the excess over the window's start divided by the window's width, rounded down to $10). The brackets collapse to 1.99% on the first $30,000 and 5.21% above, for every filing status. The deduction for one-half of self-employment tax is a federal above-the-line deduction and stays in federal AGI. The dependent exemption survives (§12-6-1140 was not amended); its 2026 indexed amount is not yet published, so the 2025 $4,930 is carried and flagged. The I-335 election (S.C. Code §12-6-545): a sole proprietor may have active trade or business income taxed at a flat 3% instead of the brackets. Under the safe harbor (Revenue Ruling #08-2), when pass-through income — net profit after its deductions, including the deductible half of self-employment tax — is $100,000 or less, half of it is treated as personal-service compensation and the other half is the active trade or business income taxed at 3%. Above $100,000 the election is still available but the filer must document the personal-services split, which the calculator does not attempt; it applies the election only within the safe harbor and only when it lowers the tax (never at taxable incomes still inside the 3% bracket). State credit (2026-09-08, two independent reads reconciled): still 125% of the federal earned income credit and nonrefundable, but Act 110 caps it at $200 from 2026. 2026-09-15: not modeled — S.C. Code §12-6-1150(A), the 44% net capital gain deduction: "Individuals, estates, and trusts are allowed a deduction from South Carolina taxable income equal to forty-four percent of net capital gain recognized in this State during a taxable year", with net capital gain "as defined in Internal Revenue Code, Section 1222 and related sections" (§12-6-1150(B)(2)). Act 110 of 2026 does not amend it, so it survives the move to a federal-AGI base. This calculator takes no capital-gain input, so the omission changes no figure it reports; it would have to be modeled before any capital gain enters the base. Note that SC1040 line i describes it more loosely as "44% of net capital gains held for more than one year", which omits the netting against short-term losses that §1222(11) requires.
Virginia 2025	verified	2026-09-08	Virginia Department of Taxation : 2025 Form 760 instructions Va. Code §58.1-320 (rates), §58.1-322.03 (standard deduction as amended by the 2025 budget), §58.1-322.03 (personal exemption $930) Virginia Department of Taxation : 2025 Form 760 and Schedule ADJ instructions: refundable Virginia earned income tax credit of 20% of the federal credit (line 16b; the former nonrefundable 20% option's lines 15 and 16a are 'reserved for future use'), or instead the credit for low-income individuals of $300 per exemption for family Virginia AGI within the poverty guideline (2025: $15,650 for one person plus $5,500 each additional), nonrefundable; Va. Code §58.1-339.8(B)(3)(b) (20% refundable through 2026, extended through 2029 by the 2026 Appropriation Act per Legislative Summary 26-82) Verification: Two independent primary-source reads on 2026-09-05 (state 2025 form instructions / rate schedules, statute or enacted 2025 legislation), reconciled; every difference from the draft corrected and logged in notes. State credits added 2026-09-08 after two independent reads of the 2025 Schedule ADJ instructions and §58.1-339.8. Notes 2026-09-05 audit: brackets, $8,750/$17,500 standard deduction (2025 Form 760 instructions, line 11; Va. Code §58.1-322.03 as amended for 2025–2026) and the $930 exemption confirmed. Head of household is not a separate Virginia filing status; it uses the single amount. Added the filing threshold: no tax when Virginia AGI is below $11,950 ($23,900 joint). The $8,750/$17,500 amounts apply to 2025 and 2026; 2026 legislation sets $9,200/$18,400 for 2027 and $9,300/$18,600 for 2028–2029. Not modeled: the spouse tax adjustment for joint filers (up to $259) and the age deduction for filers 65 and over. State credits (2026-09-08, two independent reads reconciled): the Virginia earned income tax credit is 20% of the federal credit and refundable for 2025 and 2026 (the 2025 budget raised it from 15% and the nonrefundable 20% option disappeared from the 2025 Schedule ADJ); filers within the poverty guideline may instead take $300 per exemption against the tax, and the calculator picks whichever is worth more. Both credits are denied to filers claiming the age deduction or the 65-and-over exemption, which the calculator does not collect.
Wisconsin 2025	verified	2026-09-08	Wisconsin Department of Revenue : 2025 Form 1 instructions (read from Wayback Machine captures of revenue.wi.gov, which refuses automated connections): line 1 = federal AGI (Form 1040 line 11), standard deduction schedules and tax computation worksheet, $700 exemptions, tax table rows 28,600–28,700 ($1,128 single / $1,084 joint / $1,172 separate) and 50,000–50,100 ($2,070 / $2,026 / $2,262), and the instructions' own example (joint, $28,653 → $1,084) Wisconsin Department of Revenue : individual income tax rates page and 2025 Form 1-ES instructions (post-Act 15 revision): 3.5% / 4.4% / 5.3% / 7.65% at $14,680 / $50,480 / $323,290 (single and head of household), $19,580 / $67,300 / $431,060 (joint), $9,790 / $33,650 / $215,530 (separate); the standard deduction formulas by filing status 2025 Wisconsin Act 15 §§223, 226, 227 (second bracket widened from tax year 2025) and §230 creating s. 71.06(2e)(bm) (indexing from 2026) Wisconsin Department of Revenue : 2025 Form 1 instructions, line 30 (earned income credit: 4% / 11% / 34% of the federal credit for one / two / three or more qualifying children, none for childless filers, refundable, full-year residents, not married filing separately; computed directly on the form — there is no separate schedule); Wis. Stat. §71.07(9e) Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the Form 1 instructions, the Form 1-ES rate and standard-deduction schedules and Act 15, reconciled with no differences, then attacked by a third reader who matched the standard-deduction formula to twelve printed table rows (including the head-of-household crossover) and three hand computations within the table's rounding; both readers used archived copies of the Department's PDFs because revenue.wi.gov blocks automated access. Tax-table rows, the instructions' example and the 2026 printed bases are reproduced in the test suite. State credit added 2026-09-08 after two independent reads of the Form 1 instructions. Notes 2026-09-07 audit: brackets (post-Act 15), the standard deduction formulas and the exemptions confirmed by both readers; the early-2025 printing of the 2025 Form 1-ES still showed the old second-bracket tops; the post-Act reissue carries the same 'R. 1-25' code, so the schedule, not the code, identifies the current one. Wisconsin starts from federal AGI (Form 1 line 1), so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI and Wisconsin has no subtraction for it. Standard deduction is a sliding scale: the maximum less a percentage of Wisconsin income over the phase-out start, never below zero (single: 12% of income over the start; joint and separate: 19.778%; head of household: 22.515% until the single formula gives more, at about $57,210 of income in 2025). The engine applies the formula rather than the Department's table, which rounds the same formula to whole dollars. Exemption: $700 per filer and per dependent (plus $250 per filer aged 65 or over, not modeled). State credit (2026-09-08, two independent reads reconciled): Wisconsin's earned income credit is 4%, 11% or 34% of the federal credit for one, two, or three or more children, refundable; childless filers and married filing separately get nothing. Not modeled: the married couple credit (3% of the lower earner's income up to $16,000, max $480), the school property tax / rent credit, and the additional child and dependent care credit.
Wisconsin 2026	verified	2026-09-08	Wisconsin Department of Revenue : 2026 Form 1-ES instructions (D-101A R. 1-26, Wayback capture): 2026 rate schedules (brackets $15,110 / $51,950 / $332,720 single and head of household; $20,150 / $69,260 / $443,630 joint; $10,080 / $34,630 / $221,820 separate) with the printed bases (e.g. $528.85 + 4.4% over $15,110; $2,149.81 + 5.3% over $51,950; $2,866.09 + 5.3% over $69,260 joint), and the 2026 standard deduction schedules ($13,960 / $18,030 / $25,840 / $12,280; phase-outs from $20,120 / $20,120 / $29,040 / $13,780) 2025 Wisconsin Act 15 §230 : s. 71.06(2e)(bm): brackets indexed from 2026 on an August-2024 CPI-U base; 2025 Form 1 instructions for the unchanged mechanics ($700 exemptions, formula shapes) Wisconsin Department of Revenue : 2025 Form 1 instructions, line 30 (earned income credit: 4% / 11% / 34% of the federal credit for one / two / three or more qualifying children, none for childless filers, refundable, full-year residents, not married filing separately; computed directly on the form — there is no separate schedule); Wis. Stat. §71.07(9e) Verification: Two independent reads on 2026-09-07 (the second reader blind to the first) of the Form 1 instructions, the Form 1-ES rate and standard-deduction schedules and Act 15, reconciled with no differences, then attacked by a third reader who matched the standard-deduction formula to twelve printed table rows (including the head-of-household crossover) and three hand computations within the table's rounding; both readers used archived copies of the Department's PDFs because revenue.wi.gov blocks automated access. Tax-table rows, the instructions' example and the 2026 printed bases are reproduced in the test suite. The 2026 Form 1 instructions and tax table are not yet published. State credit added 2026-09-08 after two independent reads of the Form 1 instructions and §71.07(9e) (unchanged for 2026). Notes 2026-09-07 audit: the 2026 indexed brackets and deduction schedules confirmed from the 2026 Form 1-ES; rates and exemptions unchanged. Wisconsin starts from federal AGI (Form 1 line 1), so the federal deduction for one-half of self-employment tax stays in; the federal §199A (QBI) deduction never enters AGI and Wisconsin has no subtraction for it. Standard deduction is a sliding scale: the maximum less a percentage of Wisconsin income over the phase-out start, never below zero (single: 12% of income over the start; joint and separate: 19.778%; head of household: 22.515% until the single formula gives more, at about $57,210 of income in 2025). The engine applies the formula rather than the Department's table, which rounds the same formula to whole dollars. Exemption: $700 per filer and per dependent (plus $250 per filer aged 65 or over, not modeled). State credit (2026-09-08, two independent reads reconciled): Wisconsin's earned income credit is 4%, 11% or 34% of the federal credit for one, two, or three or more children, refundable; childless filers and married filing separately get nothing. Not modeled: the married couple credit (3% of the lower earner's income up to $16,000, max $480), the school property tax / rent credit, and the additional child and dependent care credit.

Update cadence

Federal figures are refreshed when the IRS publishes the annual inflation adjustments (usually October or November) and the SSA announces the Social Security wage base. State figures are refreshed when each state publishes its form instructions for the year, typically between October and January. Mid-year legislative changes are applied when enacted and noted in the affected file.

Testing

The calculation engine has an automated test for every rule above, using hand-worked examples, and the site cannot be built if a test fails. Official worked examples from form instructions are added as tests as each data set is verified.

Differential testing

On 2026-09-06 six sets of inputs were entered into two independent calculators and compared line by line with this engine. Against TurboTax TaxCaster (tax year 2025, federal only) taxable income and total federal tax agreed within $1 on all six — including a joint return with W-2 wages and two children (child tax credit $4,400 on both), a head-of-household filer with a refundable credit, and a $200,000 profit that crosses the Social Security wage base. The one difference at the time was the earned income credit, which TaxCaster included and this calculator did not; the credit has since been added and the same case now matches TaxCaster's $4,319 of credits within $1. Against Keeper's 1099 calculator, which at the time computed with tax year 2026 parameters, taxable income, income tax and self-employment tax agreed within $1 on all comparable cases when this engine was run for 2026; Keeper's state figures for California and North Carolina did not match those states' published 2025 schedules and were not used as a reference.

The confirmed figures are pinned as tests, so a future change that moves any of them fails the build. The scripts that drive both calculators are kept in the repository so the comparison can be repeated after each annual data update.

Corrections

Maintained by Tallyvane, independent developer and publisher. To report a discrepancy, email support@clearselftax.com with the page, the inputs you used, the figure you expected and the official source for it. Confirmed corrections are applied to the data file, dated in its notes and listed on the corrections and audit log; the rules behind all of this are in the editorial policy.