The principle
Wrong tax numbers are the one failure this site cannot recover from. So the rule throughout is: a figure is either read from a primary source or it is not used. Where a number cannot be verified it is left null and the calculator declines to compute rather than guessing. Where a figure is carried forward from a prior year deliberately, the calculator still computes but emits a warning naming the year it came from.
Every line of every calculation carries the rule applied and the authority for it. OpenShow your work on the calculator to read the full derivation.
Federal sources
Inflation-adjusted figures for tax year 2026 come fromIRS Revenue Procedure 2025-32 (Internal Revenue Bulletin 2025-45). The 2026 adjusted items are in SECTION 4 of that document — not Section 3, which is taken up by modifications to the prior year’s Revenue Procedure. The widely repeated “§ 3.03” citation for the capital gains table is the previousyear’s numbering and is wrong for 2026.
| Figure | Source | Indexed? |
|---|---|---|
| Seven ordinary rate brackets, four filing statuses | Rev. Proc. 2025-32 § 4.01 (IRC 1(j)(2)) | Yes, annually |
| 0% / 15% / 20% capital gain ceilings | Rev. Proc. 2025-32 § 4.03 (IRC 1(h), 1(j)(5)) | Yes, annually |
| Standard deduction | Rev. Proc. 2025-32 § 4.14(1) (IRC 63(c)(2)) | Yes, annually |
| Net investment income tax, 3.8% | IRC 1411(a)–(b) | No — statutory since 2013 |
| Capital loss offset, $3,000 / $1,500 | IRC 1211(b) | No — unchanged since 1978 |
| Indefinite loss carryforward, character preserved | IRC 1212(b) | n/a |
| Unrecaptured § 1250 gain, 25% maximum | IRC 1(h)(1)(E), 1(h)(6); IRS Pub. 544 | No |
| Collectibles / § 1202 gain, 28% maximum | IRC 1(h)(1)(F) | No |
| Principal-residence exclusion, $250k / $500k | IRC 121(b); IRS Pub. 523 | No |
| Reduced (partial) exclusion proration | IRC 121(c); Treas. Reg. 1.121-3(g) | n/a |
| Short/long netting and loss ordering | IRC 1222; IRS Pub. 550 | n/a |
How the federal figures were checked
Rev. Proc. 2025-32 prints, for each bracket, a cumulative tax base — the$X plus 24% of the excess over $Y figure. That base is fully determined by the breakpoints beneath it, so recomputing it from the data file and comparing against the printed figure is a genuine independent check: one mistyped breakpoint changes the base. All four individual tables reconcile to the cent, and that check runs as a test on every build.
Three rules that are easy to get wrong
- MAGI for the net investment income tax is measured BEFORE the standard deduction. Using taxable income instead silently zeroes the tax for some taxpayers.
- The § 121 reduced exclusion prorates the maximum exclusion amount, not the gain (Treas. Reg. 1.121-3(g)). Prorating the gain overstates tax for anyone with a modest gain and a qualifying early sale.
- Unrecaptured § 1250 gain is the lesser of depreciation taken and total gain, and 25% is a maximum, not a flat rate — a taxpayer in the 22% bracket pays 22% on it.
State sources
State data is split into two halves with different verification calendars. Therate structure — the rate ladder, how gains are treated, exclusions, surtaxes, local add-ons — is statutory and verifiable at any time. Thethresholds — bracket bounds and standard deductions — are indexed annually and mostly published in November and December.
18 of 51 jurisdictions have a rate structure read from a tax code or revenue department. The remaining 33 are shown in the calculator as not yet available rather than left out, so no user can mistake an unverified state for a state with no tax.
| State | Source | Thresholds |
|---|---|---|
| Alaska | Tax Foundation, "2026 State Income Tax Rates and Brackets" (as of 11 Feb 2026) | Fixed in statute |
| California | Cal. Rev. & Tax. Code 17041 (ladder), 17043 (BHST surcharge) | 2025 figures, warned |
| Colorado | Colo. Rev. Stat. 39-22-104 | n/a — flat rate |
| Florida | Tax Foundation, "2026 State Income Tax Rates and Brackets" (as of 11 Feb 2026) | Fixed in statute |
| Illinois | Ill. Dept. of Revenue, Income Tax Rates (35 ILCS 5/201) | n/a — flat rate |
| Maryland | Md. Code, Tax-General 10-105 | n/a — flat rate |
| Massachusetts | Mass. Gen. Laws ch. 62 s 4 | n/a — flat rate |
| Minnesota | Minn. Stat. 290.06 subd. 2c | 2025 figures, warned |
| Nevada | Tax Foundation, "2026 State Income Tax Rates and Brackets" (as of 11 Feb 2026) | Fixed in statute |
| New Jersey | N.J. Rev. Stat. 54A:2-1 | Fixed in statute |
| New York | N.Y. Tax Law 601 | Fixed in statute |
| Ohio | Ohio Rev. Code 5747.02 | 2025 figures, warned |
| Pennsylvania | Pa. Dept. of Revenue, Tax Rates (72 P.S. 7302) | n/a — flat rate |
| South Dakota | Tax Foundation, "2026 State Income Tax Rates and Brackets" (as of 11 Feb 2026) | Fixed in statute |
| Texas | Tax Foundation, "2026 State Income Tax Rates and Brackets" (as of 11 Feb 2026) | Fixed in statute |
| Virginia | Va. Code 58.1-320 | Fixed in statute |
| Washington | RCW 82.87.040, 82.87.060; Wash. ESSB 5813 (2025) | 2025 figures, warned |
| Wyoming | Tax Foundation, "2026 State Income Tax Rates and Brackets" (as of 11 Feb 2026) | Fixed in statute |
Washington is a special case: RCW 82.87.040 imposes a 7% excise on all Washington capital gains plus an additional 2.90% on the portion above $1,000,000 — a 9.9% marginal rate. Real property is exempt outright and only long-term gains are in scope. Its standard deduction is indexed under RCW 82.87.150 and published separately from any rate table; the 2026 figure was not published when this was last checked, so the 2025 amount is used under a mandatory warning.
What is out of scope
This list is deliberately explicit. If your situation involves any of these, the number this calculator gives you is incomplete — not merely approximate.
| Not modelled | Why it matters |
|---|---|
| Alternative minimum tax (IRC 55–59) | Can change the answer for high earners with large gains. |
| Qualified small business stock (IRC 1202) | Can exclude the entire gain. Only the 28% residual rate is modelled. |
| Collectibles | The federal 28% rate is modelled, and Massachusetts’ 12%-with-50%-deduction. No other state’s collectibles treatment is. |
| Wash sales (IRC 1091) | Disallowed losses are not detected. The engine takes your net gain as given. |
| Like-kind exchanges (IRC 1031) | Deferral is not modelled. |
| Installment sales (IRC 453) | Spreading gain across years is not modelled. |
| Multiple lots and specific identification | One gain figure per sale. No per-lot basis tracking or FIFO/HIFO selection. |
| Opportunity zones (IRC 1400Z-2) | Deferral and step-up are not modelled. |
| Kiddie tax (IRC 1(g)) | A child’s unearned income above $1,350 is not handled. |
| Estates and trusts | Verified 2026 figures are recorded in the codebase but unreachable: only the four individual filing statuses are supported. |
| Net investment income beyond gains and qualified dividends | Interest, rents, royalties and passive business income are NII under IRC 1411(c). The engine derives NII from capital gains and qualified dividends only, and warns when it does. |
| State additions, subtractions and deductions | State tax is computed by stacking the gain on FEDERAL ordinary taxable income. Each state’s own base differs, and the engine warns when it approximates. |
| Local income taxes | New York City and Yonkers, Maryland counties, Ohio municipalities, Indiana counties, Michigan cities. Flagged in a warning, never silently omitted. |
| Non-residents and part-year residents | Every state figure assumes full-year residency. |
Corrections
If you find a figure that is wrong, pleasetell us and cite the source. Corrections to tax figures are treated as urgent. Source data for tax year 2026 isRev. Proc. 2025-32 (I.R.B. 2025-45).