State tax docs / Verification
How the state tax engine is verified
What is tested, against what, and where the testing stops. The status of each state below is an audit of the test suite and the engine's cited sources as they stand, not a statement of confidence.
Golden scenarios
155 rows in the engine's golden-scenario file each carry an expected federal tax, state tax and Medicare surcharge computed by hand, independently of the engine, from the published rules. The suite runs the engine on every row and fails if any result is more than $1 away. When a row's derivation follows a state's own form or worksheet line by line, the row says so, and that is what the worksheet-tested class below counts.
Unit tests
The state-tax unit suite has tests for individual rules (a state's exclusion cap, its Social Security formula, its married-filing-separately schedule) and structural tests over every jurisdiction: each state resolves, every bracket table is contiguous with non-decreasing rates, no state uses a placeholder schedule, and calls without a spouse split give results identical to the pooled household calculation.
Status classes
- Worksheet-tested Worksheet-tested: at least one golden scenario or unit test pins an exact dollar result for this state, hand-computed independently of the engine, and the test's own derivation names the state form, worksheet or rate schedule it follows.
- Statute and instructions cited Statute and instructions cited: the engine's rules for this state cite the state's statute, instructions or tax agency, and tests pin its rules, but no test derivation follows a named state worksheet.
- Rate table only Rate table only: the state's rate schedule and deductions are its only state-specific inputs and the engine cites only a rate-table compilation for them.
- No income tax No broad personal income tax: nothing to compute beyond any special levy the page lists.
Counts: worksheet-tested 18; statute and instructions cited 24; rate table only 0; no income tax 9.
Per-state status
| Jurisdiction | Status | Golden rows | State-specific unit tests | Basis |
|---|---|---|---|---|
| Alabama | Worksheet-tested | 7 | 7 | Golden rows follow the Form 40 federal-income-tax worksheet and Schedule RS (per-spouse line 10). |
| Alaska | No income tax | 0 | 0 | No broad personal income tax; the engine returns zero, and the golden scenarios include no-tax rows. |
| Arizona | Statute and instructions cited | 1 | 2 | Rate, deduction and the 25% long-term-gain subtraction cited to statute; one golden row. |
| Arkansas | Statute and instructions cited | 1 | 6 | Exact tests of the $6,000 exemption, its IRA age gate and conversions, derived from the statute and the AR1000F booklet cited in the engine. |
| California | Statute and instructions cited | 6 | 15 | Brackets from the Franchise Tax Board's indexed schedule and the mental health services tax from statute; golden rows and unit tests pin them. |
| Colorado | Worksheet-tested | 4 | 11 | Golden and unit tests follow form DR 0104 line 1 (federal taxable income) and DR 0104AD line 4 (the pension and Social Security subtraction). |
| Connecticut | Worksheet-tested | 4 | 11 | Unit and golden tests follow the CT-1040 Tax Calculation Schedule (Tables C and D) and the Social Security benefit adjustment worksheet. |
| Delaware | Worksheet-tested | 5 | 8 | Golden and unit tests follow the PIT-RES instructions, Line 6 pension exclusion worksheet (including the per-taxpayer columns). |
| District of Columbia | Worksheet-tested | 3 | 3 | An engine 1.2.0 test follows the 2026 D-40ES head-of-household deduction; golden rows pin the schedule. |
| Florida | No income tax | 1 | 1 | No broad personal income tax; the engine returns zero, and the golden scenarios include no-tax rows. |
| Georgia | Statute and instructions cited | 6 | 10 | Exclusion tiers and pooling cited to O.C.G.A. 48-7-27 and Form 500 Schedule 1; golden rows pin them. |
| Hawaii | Statute and instructions cited | 5 | 2 | The employer-funded pension exemption and the capital-gains alternative tax cited to HRS; golden rows pin them. |
| Idaho | Statute and instructions cited | 1 | 5 | Rate and the 0% band cited to Idaho Code 63-3024; one golden row. |
| Illinois | Statute and instructions cited | 2 | 7 | Full retirement exclusion and exemption cited to statute and IDOR; golden rows pin them. |
| Indiana | Statute and instructions cited | 1 | 2 | Senior exemptions and the county tax cited to the Indiana Code and Departmental Notice #1; a golden row pins them. |
| Iowa | Statute and instructions cited | 2 | 3 | Full exclusion at 55 and the federal-taxable-income starting point cited to Iowa law and the IA 1040 instructions; golden rows pin them. |
| Kansas | Statute and instructions cited | 2 | 1 | Public-pension exemption and personal exemption cited to K.S.A.; golden rows pin them. |
| Kentucky | Worksheet-tested | 0 | 1 | A unit test pins the $31,110 exclusion drawn by a Roth conversion, following Schedule P. |
| Louisiana | Worksheet-tested | 4 | 5 | Golden rows follow the IT-540 instructions' Schedule E code 06E definition of retirement income, including per-spouse rows. |
| Maine | Worksheet-tested | 3 | 6 | Golden rows follow the Form 1040ME instructions, including the Schedule 1S pension deduction and its conversion rule. |
| Maryland | Statute and instructions cited | 4 | 8 | The pension exclusion, capital-gains surcharge and county tax cited to the Comptroller; golden rows pin them. |
| Massachusetts | Statute and instructions cited | 0 | 2 | Flat rate and the 4% surtax cited to the Department of Revenue; unit tests pin them. |
| Michigan | Statute and instructions cited | 0 | 2 | The retirement deduction is cited to Treasury guidance and pinned by an exact unit test. |
| Minnesota | Statute and instructions cited | 2 | 4 | Brackets, head-of-household schedule and the Social Security subtraction cited to the Department of Revenue; golden rows pin them. |
| Mississippi | Statute and instructions cited | 3 | 4 | Full exclusion, exemptions and the 0% band cited to the Mississippi Code and DOR; golden rows pin them. |
| Missouri | Worksheet-tested | 9 | 13 | Golden and unit tests follow Form MO-A Part 3 Sections A, B and C line by line, including the per-spouse columns. |
| Montana | Worksheet-tested | 1 | 2 | A golden row follows Form 2 line 3 (federal taxable income less federal deductions). |
| Nebraska | Worksheet-tested | 0 | 2 | Engine 1.2.0 tests follow the 2026 Form 1040N-ES rate schedules, including head of household. |
| Nevada | No income tax | 0 | 0 | No broad personal income tax; the engine returns zero, and the golden scenarios include no-tax rows. |
| New Hampshire | No income tax | 0 | 0 | No broad personal income tax; the engine returns zero, and the golden scenarios include no-tax rows. |
| New Jersey | Worksheet-tested | 2 | 4 | Engine 1.2.0 tests follow the NJ-1040 pension exclusion worksheet (band percentage of the whole pension) and Tables A and B. |
| New Mexico | Statute and instructions cited | 4 | 4 | Social Security thresholds and the capital-gain deduction cited to NMSA; golden rows pin them. |
| New York | Worksheet-tested | 8 | 11 | Engine 1.2.0 tests follow the 2026 IT-2105-I tax rate schedules and recapture worksheets, including the head-of-household schedule. |
| North Carolina | Statute and instructions cited | 1 | 0 | Rate and deductions cited to the NCDOR and statute; one golden row. |
| North Dakota | Worksheet-tested | 1 | 4 | Engine 1.2.0 tests follow the 2026 ND-1ES rate schedules for single, joint and head of household. |
| Ohio | Statute and instructions cited | 1 | 4 | Rate schedule cited to the Revised Code; one golden row. |
| Oklahoma | Worksheet-tested | 4 | 8 | Golden and unit tests follow Schedule 511-A line 6, including the per-person exclusion. |
| Oregon | Statute and instructions cited | 2 | 2 | The capped federal-tax subtraction and exemption credit cited to ORS and Publication OR-17; golden rows pin them. |
| Pennsylvania | Statute and instructions cited | 2 | 4 | Full exclusion and the taxation of gains cited to the Pennsylvania Code and DOR answers; golden rows pin them. |
| Rhode Island | Statute and instructions cited | 6 | 5 | The pension modification and the Social Security test cited to the Division of Taxation's Retirement Income Guide; golden rows pin them. |
| South Carolina | Statute and instructions cited | 6 | 6 | The retirement and age-65 deductions cited to the SC Code and a revenue ruling; golden rows pin them. |
| South Dakota | No income tax | 0 | 0 | No broad personal income tax; the engine returns zero, and the golden scenarios include no-tax rows. |
| Tennessee | No income tax | 0 | 0 | No broad personal income tax; the engine returns zero, and the golden scenarios include no-tax rows. |
| Texas | No income tax | 33 | 1 | No broad personal income tax; the engine returns zero, and the golden scenarios include no-tax rows. |
| Utah | Statute and instructions cited | 0 | 7 | The taxpayer credit and the Social Security credit cited to the Utah Code; exact unit tests pin them. |
| Vermont | Statute and instructions cited | 1 | 7 | The Social Security phase-out and the $5,000 gain exclusion cited to statute and the Department of Taxes; a golden row and unit tests pin them. |
| Virginia | Worksheet-tested | 3 | 5 | Golden and unit tests follow the Form 760 Age Deduction Worksheet (lines 9 to 15). |
| Washington | No income tax | 0 | 2 | No income tax. The capital-gains excise (RCW 82.87) is pinned by an exact unit test. |
| West Virginia | Worksheet-tested | 1 | 5 | A unit test follows the IT-140 Rate Schedule II for married filing separately. |
| Wisconsin | Worksheet-tested | 3 | 3 | Engine 1.2.0 tests follow the 2026 Form 1-ES standard-deduction table, including the head-of-household and MFS rows. |
| Wyoming | No income tax | 0 | 0 | No broad personal income tax; the engine returns zero, and the golden scenarios include no-tax rows. |
Gates
- The engine test suite (unit tests and golden scenarios) runs inside the engine's container build, so an engine that fails a test cannot be built for deployment.
- This documentation is generated from the engine's dump. A docs gate rebuilds the dump from the engine source and fails if it differs from the committed copy, regenerates every page and fails if any differs, and fails if a state page carries a rule with no source, a source with no checked date, or a source checked against a value the engine no longer holds.
- Every other page that restates a state rate or rule (state pages, comparisons, the 51-state study and dataset) is held to the engine's own dump by separate gates.
Recurring checks
- Weekly: every provenance source is fetched; a dead link, a redirect to a different page, or a missing checked figure is reported, and a failure that persists across two weekly runs pages the operator.
- Nightly: realistic households run through the live production engine and are checked against the product's published claims; for state tax this confirms that a taxing state changes the outcome relative to a no-tax state.
Open differences between a source and the engine
| State | Rule | Source says | Engine | Note |
|---|---|---|---|---|
| AZ | Capital gains | 25% subtraction only for assets acquired after December 31, 2011 | 75% | The engine assumes gains are on assets bought after 2011 (75% taxed); it has no acquisition-date input, so gain on older assets is under-taxed by 2.5% of 25% of it. |
| NY | IRA, 401(k) and private pensions | 59½ | age 59 | The engine's age test is a whole year (59); the statute's is 59½. |
| RI | IRA, 401(k) and private pensions | $133,500 (Pub 2026-01) vs $133,750 (ADV 2025-22) | $133,750 | Rhode Island's own documents disagree ($133,500 in Pub 2026-01, $133,750 in ADV 2025-22); the engine uses the advisory figure. |
Rules without an official source
| State | Rule | Why |
|---|---|---|
| ID | Social Security | No official Idaho source could be fetched: tax.idaho.gov and legislature.idaho.gov (and every *.idaho.gov host tried) refuse connections from this host. No secondary source for Idaho's Social Security exemption was verified either. |
| ID | IRA, 401(k) and private pensions | No official page states in terms that Idaho has no general retirement exclusion; Idaho Code 63-3022A (see Public pensions and Military retirement pay) lists the only retirement benefits Idaho deducts. |
| ID | Roth conversions | No official Idaho source could be fetched: tax.idaho.gov and legislature.idaho.gov (and every *.idaho.gov host tried) refuse connections from this host. |
| ID | Capital gains | No official Idaho source could be fetched: tax.idaho.gov and legislature.idaho.gov (and every *.idaho.gov host tried) refuse connections from this host. |
| TX | No broad income tax | No official Texas source could be fetched from the checker host (DNS resolution fails for all Texas state domains); only the Tax Foundation 2026 table (secondary) is recorded. Re-run from a host with working DNS for texas.gov and add Tex. Const. art. 8, §24-a (statutes.capitol.texas.gov/Docs/CN/htm/CN.8.htm) as the official source. |
| WV | Deductions, exemptions and credits | The $2,000 personal exemption (W. Va. Code §11-21-16) could not be sourced: code.wvlegislature.gov and the www.wvlegislature.gov code viewer redirect this host to an unrelated page, and tax.wv.gov timed out on 2026-09-27; no fetched enrolled bill restates the exemption amount. |
Sources on the state pages: 627 citations across 380 rule sections.