Methodology and Sources
Every rate, bracket and filing rule on IncomeTaxByState.com traces to a published source: the state's own Department of Revenue, IRS Publication 17, the Federation of Tax Administrators, the Tax Foundation State Business Tax Climate Index, NCSL legislative tracking, and the US Bureau of Labor Statistics for income-level reference points. This page documents the source ledger, the calculation framework and the refresh cadence.
Primary sources
Every state with a dedicated page on this site has a verification URL pointing to the state's Department of Revenue or Department of Taxation. The table below names the source, the URL and what we take from it. Where a state has a dedicated page on this site, we have walked the verification trail to the published bracket table on the state's own page.
| Source | What we take from it | Refresh |
|---|---|---|
| IRS Publication 17 (Your Federal Income Tax) | Federal baseline; standard deduction, filing status definitions and federal AGI references that state systems conform to or modify. | Annual (early calendar year). |
| IRS State Filing Information | Canonical IRS-maintained directory of state revenue department websites; the entry point for primary-source verification per state. | Annual. |
| Federation of Tax Administrators (FTA) | State Individual Income Tax Rates and Brackets table; cross-check against each state's own DOR publication. | Updated as states pass legislation; annual roll-up. |
| Tax Foundation State Business Tax Climate Index | Independent cross-reference for state rate trends and structural notes (flat vs graduated, conformity to federal code, local-tax treatment). | Annual (autumn release). |
| NCSL State Tax Data | Legislative tracking for state tax actions; useful for identifying mid-year rate changes and effective-date schedules. | Continuous; annual State Tax Actions report. |
| California Franchise Tax Board | Primary source for California brackets, standard deduction, filing thresholds, residency rules and forms 540 / 540NR. | Annual (December prior year). |
| New York Department of Taxation and Finance | Primary source for NY State brackets, NYC and Yonkers surcharges, IT-201 forms, statutory residency rule, convenience-of-employer rule. | Annual. |
| Texas Comptroller of Public Accounts | Primary source confirming Texas has no personal income tax; franchise tax, sales and use tax references. | Annual. |
| Florida Department of Revenue | Primary source confirming Florida has no personal income tax; corporate income tax, sales tax, documentary stamp tax. | Annual. |
| Pennsylvania Department of Revenue | Primary source for PA flat 3.07% rate, PA-40 form, retirement income exemption rules, NJ-PA reciprocity. | Annual. |
| Illinois Department of Revenue | Primary source for IL flat 4.95% rate, personal exemption, retirement income exemption (pensions, 401(k), IRA all exempt). | Annual. |
| Ohio Department of Taxation | Primary source for Ohio state brackets (2.75% and 3.75% top), plus municipal-tax framework collected via RITA and CCA. | Annual; municipal rates updated continuously. |
| New Jersey Division of Taxation | Primary source for NJ 7-bracket structure (1.4% to 10.75%), MFJ tables, ANCHOR property tax relief context, NJ-PA reciprocity. | Annual. |
| Georgia Department of Revenue | Primary source for GA 5.39% flat rate (2026), legislated glide path to 4.99%, $65,000 retirement exclusion at age 65+. | Annual. |
| Massachusetts Department of Revenue | Primary source for MA 5% flat rate plus 4% Fair Share Amendment surtax above $1M, personal exemptions, rental deduction. | Annual. |
| Michigan Department of Treasury | Primary source for MI 4.05% flat rate plus Detroit 2.4% / 1.2% non-resident, Grand Rapids / Lansing / Pontiac local rates, pension subtraction. | Annual. |
| Arizona Department of Revenue | Primary source for AZ 2.5% flat rate (2023+), standard deduction, retirement treatment, no-Social-Security-tax confirmation. | Annual. |
| Colorado Department of Revenue (Taxation) | Primary source for CO 4.4% flat rate, TABOR refund context, federal-conformity notes. | Annual. |
| Minnesota Department of Revenue | Primary source for MN graduated brackets 5.35% to 9.85%, Social Security taxation thresholds. | Annual. |
| Hawaii Department of Taxation | Primary source for HI 12-bracket structure 1.4% to 11%, retirement exemptions. | Annual. |
| Oregon Department of Revenue | Primary source for OR brackets 4.75% to 9.9%, kicker-refund mechanism, retirement treatment. | Annual. |
| Maryland Comptroller | Primary source for MD state brackets plus all 23 counties + Baltimore City local income tax rates (1.75% to 3.20%). | Annual. |
| Indiana Department of Revenue | Primary source for IN 3.05% flat state rate plus all 92 county local income taxes. | Annual. |
| Wisconsin Department of Revenue | Primary source for WI graduated brackets 3.5% to 7.65%, retirement treatment. | Annual. |
| Virginia Tax | Primary source for VA brackets 2% to 5.75%, DC suburb reciprocity context. | Annual. |
| AICPA Tax Practice Resources | Professional cross-reference for technical interpretation of state tax rules and conformity to federal code. | Continuous. |
| US Bureau of Labor Statistics (BLS) | Median wage and income distribution data used to choose representative income levels ($50K / $75K / $100K / $250K) for worked examples. | Quarterly / annual. |
States not listed in the table above (Alabama, Arkansas, Connecticut, Delaware, Idaho, Iowa, Kansas, Kentucky, Louisiana, Maine, Mississippi, Missouri, Montana, Nebraska, New Mexico, North Carolina, North Dakota, Oklahoma, Rhode Island, South Carolina, Utah, Vermont, West Virginia, plus DC) are verified against their respective Department of Revenue or Department of Taxation; the verification URL appears on each state's dedicated page.
Calculation framework
Marginal vs effective rate
Every per-state page applies brackets only to the income within each bracket, never to total income. The effective rate is total state tax divided by gross income (not taxable income), expressed as a percentage. Worked examples show the bracket-by-bracket build-up so any reader can audit the arithmetic against the state DOR's published bracket table.
Standard deduction handling
Most state calculators apply the state's own standard deduction before the bracket math. Some states (Illinois) use a personal exemption instead. Some states (Pennsylvania) do not allow a standard deduction at all. Each state page documents which mechanism applies and the 2026 figure.
Flat vs graduated
14 states use a flat rate (one rate on all taxable income). 27 states plus DC use graduated brackets. 9 states levy no personal income tax. The /flat-tax-states, /graduated-rate-states and /no-income-tax-states pages group all 50 by structure. Massachusetts is hybrid: 5% flat plus a 4% surtax on income above $1M (the Fair Share Amendment).
Local income tax stacking
16 states allow city or county income taxes that stack on top of the state rate. We document the largest local taxing authorities per state: NYC (3.078% to 3.876%), Yonkers (16.75% state-tax surcharge), Philadelphia (3.75% resident / 3.44% non-resident), Detroit (2.4% / 1.2%), all 23 Maryland counties (1.75% to 3.20%), all 92 Indiana counties, 600+ Ohio municipalities. See /local-income-tax for the full reference.
Reciprocity agreements
16 states have reciprocity agreements that let residents of one state work in another and pay only home-state income tax. The most important: NJ-PA, DC-MD-VA-WV, OH and several Midwest states. We document the agreement on each affected state's page. New York applies the convenience-of-employer rule, which can override reciprocity expectations.
Residency tests
Each state defines residency differently. California uses a domicile test. New York uses a 183-day statutory residence rule plus domicile. Most states use a 183-day default. We surface the residency rule on each state page because it determines whether worldwide income or just state-source income is taxed.
In scope
- Statutory state income tax brackets and rates as published by each state DOR.
- State standard deduction, personal exemption and filing status thresholds.
- Effective rate calculations at $50K / $75K / $100K / $250K reference incomes (single filer, standard deduction).
- Local income taxes that stack on top of the state rate (cities, counties, school districts).
- Retirement income treatment (Social Security, pensions, 401(k), IRA, military pension).
- Filing rules for residents, part-year residents and non-residents, plus reciprocity agreements.
Out of scope
- Federal income tax calculations beyond noting state conformity (see effectivetaxratecalculator.com).
- FICA (Social Security and Medicare withholding) calculations (see aftertaxincomecalculator.com).
- Property tax, sales tax and other non-income state taxes beyond brief context on no-tax states.
- Itemized deductions: we use standard deduction in worked examples because that is the default for most taxpayers.
- State credits (earned income credit, child credit, education credit, etc.): noted where material, not exhaustively listed.
- Estate, inheritance and gift taxes at the state level.
Refresh cadence
The site is fully re-verified on an annual cycle, with the primary refresh window in January after most state legislative sessions adjourn and January 1 effective dates settle. The 2026 cycle captured a major batch of state rate changes effective January 1, 2026: Iowa completed its transition to a flat 3.9% rate; Mississippi reduced its rate from 4.7% to 4.4%; Kentucky reduced from 4.0% to 3.5%; Nebraska reduced its top from 5.84% to 4.55%; Oklahoma collapsed six brackets to three with a top of 4.5%; North Carolina reduced from 4.5% to 3.99%; Georgia continued its glide path from 5.49% to 5.39%.
Out-of-cycle refresh triggers:
- A state passes legislation changing rates, brackets or filing rules mid-year.
- A state announces a special-session rate change (rare, but happened with several states' 2022 surplus rebates).
- A federal change (TCJA expiration, IRS Publication 17 update) materially affects state conformity.
- A reader correction identifies an error against the state DOR's published figure.
- A new state DOR publication is issued (inflation-adjusted bracket thresholds typically refresh in December for the next year).
The LAST_VERIFIED_DATE in the site source code moves only when a real review pass has happened. Cosmetic date bumps are not made. The "Updated May 2026" stamp on every page corresponds to the same single-source ISO date in the site code.
YMYL limitations and disclaimers
Income tax filing is Your Money Your Life territory. Material errors carry real penalties and back-tax exposure. This site is a reference, not advice. The calculator outputs are estimates that apply standard deduction and the state's published brackets; they do not capture itemized deductions, state credits, federal-state interactions, residency edge cases, multi-state filing or self-employment tax.
Before filing, always:
- Confirm current-year rates with your state Department of Revenue's own publication.
- Consult a licensed CPA, Enrolled Agent or tax attorney for advice on your specific circumstances, especially for multi-state, high-income, business-owner, retirement-transition or convenience-of-employer situations.
- Read the IRS instructions for the current tax year if you have any federal-state interaction questions.
If a figure on this site disagrees with the state DOR's own publication, the state DOR is authoritative. Email [email protected] with the URL and the discrepancy; we correct errors within 5 business days.
Not published on this site
- Specific tax preparation advice for individual circumstances.
- Estimates that bake in itemized deductions, state-specific credits or federal-state interaction edge cases.
- Forecasts of future rate changes beyond what state legislatures have already enacted into law with a published effective date.
- State-by-state comparison rankings, beyond the structural sort by top rate or effective rate.
- Tax-software vendor reviews; affiliate links to TurboTax, TaxAct and FreeTaxUSA are present but are not editorial recommendations.
Last reviewed May 2026. Read more about who builds this →