Sources
No tax number ships without provenance. Here is every official source behind the figures in this calculator, with the date each was last verified.
Federal — IRS & SSA
Tax year 2026 · last verified June 17, 2026
- IRS Revenue Procedure 2025-32 (drop PDF) — Section 4.01 Tax Rate Tables and Section 3.14 Standard Deduction, tax year 2026 — All federal income tax bracket thresholds and standard deduction amounts for Single, MFJ, MFS, and HoH
- Internal Revenue Bulletin 2025-45 (published Rev. Proc. 2025-32) — Independent verification of HoH and MFS bracket thresholds (Tables 2 and 4)
- IRS Newsroom: IRS releases tax inflation adjustments for tax year 2026 (IR-2025-103) — Independent corroboration of Single and MFJ brackets and all four standard deductions
- IRS Topic No. 751 — Social Security and Medicare withholding rates — Medicare HI employee rate (1.45%), no Medicare wage base limit
- IRS Topic No. 560 — Additional Medicare Tax — 0.9% Additional Medicare Tax rate and filing-status thresholds ($250k MFJ, $125k MFS, $200k single/HoH)
- IRS Instructions for Form 8959 — Additional Medicare Tax — Confirms 0.9% rate and per-filing-status thresholds are not indexed for inflation
- IRS Publication 15 (2026), Circular E — Medicare 1.45% rate, no Medicare wage base limit
- SSA Office of the Chief Actuary — Contribution and Benefit Base — 2026 OASDI employee rate (6.2%) and 2026 Social Security wage base ($184,500)
- SSA 2026 Cost-of-Living Adjustment (COLA) Fact Sheet — 2026 Social Security taxable maximum ($184,500)
- SSA Press Release — Social Security Announces 2.8 Percent Benefit Increase for 2026 — Confirms 2026 taxable maximum rises to $184,500 from the 2025 base of $176,100
States
Each state page links to its own official source. Sources verified so far:
- Alabama: Alabama Department of Revenue — Individual Income Tax Rate (2% / 4% / 5%) + federal income tax deduction (verified June 17, 2026)
- Alaska: Alaska Department of Revenue — Tax Division (verified June 17, 2026)
- Arizona: Arizona Form 140ES (2026) Individual Estimated Income Tax booklet — flat 2.5% rate (verified June 17, 2026)
- Arkansas: Arkansas Department of Finance and Administration — Individual income tax (verified June 18, 2026)
- California: California Franchise Tax Board — Tax rate tables (Form 540) (verified June 18, 2026)
- Colorado: Colorado General Assembly — SB24-228 (TABOR refund mechanisms): 4.40% baseline for tax years 2025+ (verified June 17, 2026)
- Connecticut: Connecticut Department of Revenue Services — Income tax calculators and tables (verified June 18, 2026)
- Delaware: Delaware Code Title 30, Ch. 11, Subchapter I, §1102 — individual income tax rate schedule (0%–6.6%, seven brackets) (verified July 2, 2026)
- Florida: Florida Department of Revenue (verified June 17, 2026)
- Georgia: Office of the Governor of Georgia — Gov. Kemp signs HB 463 lowering the income tax to 4.99% (May 2026) (verified June 17, 2026)
- Hawaii: Hawaii Department of Taxation — Tax rate schedules (verified June 18, 2026)
- Idaho: Idaho State Tax Commission — Individual Income Tax Rate Schedule (verified June 17, 2026)
- Illinois: Illinois Department of Revenue — 2026 IL-700-T Withholding Income Tax Tables (4.95%, effective Jan 1, 2026) (verified June 17, 2026)
- Indiana: Indiana Department of Revenue — Rates, Fees & Penalties (state rate 2.95% for 2026, IC 6-3-2-1) (verified June 17, 2026)
- Iowa: Iowa Department of Revenue — IDR Announces 2026 Individual Income Tax Rates (flat 3.8%) (verified June 17, 2026)
- Kansas: Kansas Department of Revenue — 2025 Individual Income Tax Booklet (IP-25): two brackets 5.20% / 5.58% (verified June 17, 2026)
- Kentucky: Kentucky Department of Revenue — 2026 Kentucky Withholding Tax Formula (3.5%, std deduction $3,360) (verified June 17, 2026)
- Louisiana: Louisiana Department of Revenue — Income Tax Reform FAQ (flat 3% rate and increased standard deduction) (verified June 17, 2026)
- Maine: Maine Revenue Services — Individual income tax (1040ME) rate schedules (verified June 18, 2026)
- Maryland: Comptroller of Maryland — Maryland income tax rates and brackets (verified June 18, 2026)
- Massachusetts: Massachusetts Department of Revenue — Massachusetts tax rates (verified June 18, 2026)
- Michigan: Michigan Department of Treasury — 2026 individual income tax rate determined (4.25%) (verified June 17, 2026)
- Minnesota: Minnesota Department of Revenue — 2026 income tax brackets, standard deduction & dependent exemption (press release Dec 16, 2025) (verified June 17, 2026)
- Mississippi: Mississippi House Bill 1 (2025), 'Build Up Mississippi Act' amending Miss. Code §27-7-5 (4% for 2026) (verified June 17, 2026)
- Missouri: Missouri Department of Revenue — Individual Income Tax (graduated rates, top 4.7% for 2026; conforms to the federal standard deduction) (verified June 17, 2026)
- Montana: Montana Department of Revenue — HB 337 (2026 rates: 4.7% / 5.65%) (verified June 17, 2026)
- Nebraska: Nebraska Department of Revenue — 2025 Individual Income Tax: Tax Calculation Schedule (1040N) + standard deduction (Booklet) (verified June 21, 2026)
- Nevada: Nevada Department of Taxation (verified June 17, 2026)
- New Hampshire: Repeal of NH Interest & Dividends Tax Now in Effect — NH Dept. of Revenue Administration (verified June 17, 2026)
- New Jersey: New Jersey Division of Taxation — Tax rate schedules (verified June 18, 2026)
- New Mexico: New Mexico Taxation & Revenue Department — Personal Income Tax Rates (§7-2-7 NMSA schedule) (verified July 2, 2026)
- New York: New York State Department of Taxation and Finance — Tax tables (verified June 18, 2026)
- North Carolina: North Carolina Department of Revenue — Tax Rate Schedules (flat 3.99% for 2026, G.S. 105-153.7) (verified June 17, 2026)
- North Dakota: North Dakota Office of State Tax Commissioner — Individual Income Tax (0% / 1.95% / 2.50% for 2026; starts from federal taxable income) (verified June 17, 2026)
- Ohio: Ohio Department of Taxation — Individual income tax (verified June 18, 2026)
- Oklahoma: Oklahoma Tax Commission — 2025 Legislative Update (HB 2764): three positive brackets, top rate 4.5% effective 2026 (verified June 17, 2026)
- Oregon: Oregon Department of Revenue — Personal Income Tax (4.75%–9.9%; federal tax subtraction) (verified June 17, 2026)
- Pennsylvania: Pennsylvania Department of Revenue — Personal Income Tax Rates (flat 3.07%) (verified June 17, 2026)
- Rhode Island: Rhode Island Division of Taxation — ADV 2025-22 (2026 inflation-adjusted brackets, standard deduction & exemption) (verified June 17, 2026)
- South Carolina: South Carolina Department of Revenue — Information about H. 4216 (2026 income tax overhaul) (verified June 18, 2026)
- South Dakota: Taxes — South Dakota Department of Revenue (verified June 17, 2026)
- Tennessee: HIT-3 — Hall Income Tax Repealed Beginning January 1, 2021 — TN Dept. of Revenue (verified June 17, 2026)
- Texas: Taxes — Texas Comptroller of Public Accounts (verified June 17, 2026)
- Utah: Utah Governor's Office — SB 60 'Income Tax Rate Amendments' signed (rate cut to 4.45%, effective 2026) (verified June 17, 2026)
- Vermont: Vermont Department of Taxes — Rate Schedules (3.35% / 6.6% / 7.6% / 8.75%) and standard deduction + personal exemption (verified June 17, 2026)
- Virginia: Virginia Department of Taxation — Tax Rate Schedule (2% / 3% / 5% / 5.75%) (verified June 17, 2026)
- Washington: Income tax — Washington Department of Revenue (verified June 17, 2026)
- West Virginia: West Virginia Tax Division — 2026 Income Tax Rate Cut (SB 392) (verified June 18, 2026)
- Wisconsin: Wisconsin Department of Revenue — Tax rates (FAQ) (verified June 18, 2026)
- Wyoming: Wyoming Department of Revenue (verified June 17, 2026)