Sources

All figures were read from these documents on October 5, 2026. Only sources that supply a number or rule used by the calculator are listed. Entries marked retrieved via browser or archive were read through a headless web browser or a dated Internet Archive copy of the agency's own page because the agency blocks automated clients.

Federal

• Publication 15 (Circular E), Employer's Tax Guide — 2026 — Internal Revenue Service; For use in 2026. Supplies: 22% optional flat rate and 37% mandatory rate over $1 million of supplemental wages; aggregate procedure; 2026 Social Security wage base $184,500; Medicare 1.45%; Additional Medicare Tax 0.9% over $200,000.
• Publication 15-T (2026), Federal Income Tax Withholding Methods — Internal Revenue Service; 2026. Supplies: Worksheet 1A and the 2026 Annual Percentage Method tables (Standard and Step 2 checkbox) used by the aggregate method.
• Revenue Procedure 2025-32 (2026 inflation adjustments) — Internal Revenue Service; Taxable years beginning in 2026. Supplies: 2026 tax rate tables and standard deductions used for the annual-tax estimate.
• 401(k) limit increases to $24,500 for 2026 (IR-2025-111) — Internal Revenue Service; November 13, 2025. Supplies: 2026 elective deferral limit $24,500 and catch-up limits.

States and DC

Alabama

• Withholding Tax Tables and Instructions for Employers and Withholding Agents — Alabama Department of Revenue; Booklet 01/26. Supplies: optional 5% rate on bonuses and supplemental wages.

Alaska

• Alaska Department of Revenue, Tax Division — Alaska Department of Revenue; Read 2026-10-05. Supplies: the Tax Division publishes no individual income tax withholding tables or employee withholding forms (site checked 2026-10-05).

Arizona

• Employer's Instructions for Arizona Form A-4 (2026) and Form A-4 (2026) — Arizona Department of Revenue; 2026. Supplies: withholding is the employee-elected percentage (0.5%–3.5%) of gross taxable wages; 2.0% default.

Arkansas

• Withholding Tax Instructions for Employers — Arkansas Department of Finance and Administration; Effective 01/01/2026. Supplies: 3.9% on bonuses and commissions.

California

• California Employer's Guide 2026 (DE 44) — California Employment Development Department; 2026. Supplies: 10.23% on bonuses and stock options, 6.6% on other supplemental wages; 2026 SDI rate 1.3% with no wage limit.

Colorado

• 2026 Colorado Withholding Worksheet for Employers (DR 1098) — Colorado Department of Revenue; DR 1098 (10/21/25). Supplies: 4.40% of annualized wages above a $5,500 ($11,000 joint) allowance.

Connecticut

• Informational Publication 2026(1), Connecticut Employer's Tax Guide (Circular CT), incl. TPG-211 2026 Withholding Calculation Rules — Connecticut Department of Revenue Services; Effective January 1, 2026 (Rev. 12/25). Supplies: aggregate-only supplemental rule; withholding Tables A–E; 6.99% when no CT-W4.
• Form CT-W4 Employee's Withholding Certificate — Connecticut Department of Revenue Services; Effective January 1, 2026 (Rev. 12/25). Supplies: withholding code definitions A, B, C, D, F.

Delaware

• Employer's Guide (Withholding Regulations and Employer's Duties) — Delaware Division of Revenue; Tax Computation Table effective January 1, 2025. Supplies: annualized supplemental method, $3,250/$6,500 standard deduction, $110 exemption credit, rate table.

District of Columbia

• DC Individual and Fiduciary Income Tax Rates — DC Office of Tax and Revenue; Tax years beginning after 12/31/2021. Supplies: DC rate schedule (4%–10.75%) used for the DC estimate.
• OTR Tax Notice 2022-08, District of Columbia Withholding for Tax Year 2022 — DC Office of Tax and Revenue; October 17, 2022 (latest notice linked from the OTR withholding page; page read via the Internet Archive because the live page returns 403) (retrieved via browser or archive). Supplies: OTR does not produce withholding tables; employers are told to use the rate schedule.

Florida

• Florida Constitution, Article VII, Section 5 — Florida Legislature; Current text. Supplies: limits any tax on the income of natural persons to the amount creditable against federal tax.

Georgia

• Employer's Withholding Tax Guide 2026 (updated September 2026) — Georgia Department of Revenue; Updated September 2026. Supplies: bonus withholding at the rate in effect when paid: 5.19% before May 11, 2026; 4.99% from May 11, 2026.

Hawaii

• Booklet A, Employer's Tax Guide (Rev. 2025), Appendix effective for withholding January 1, 2026 — Hawaii Department of Taxation; Appendix effective as of December 5, 2025 for withholding January 1, 2026 and thereafter. Supplies: aggregate-only supplemental rule; $1,144 allowance; $4,350 extra allowance; annual rate tables.

Idaho

• Computing Idaho withholding (Supplemental wages) and Table for Percentage Computation Method (EPB00744) — Idaho State Tax Commission; EPB00744 dated 07-23-2026. Supplies: 5.3% of a separately issued supplemental payment.

Illinois

• 86 Ill. Adm. Code 100.7050(c) and Booklet IL-700-T (2026) — Illinois Department of Revenue / Joint Committee on Administrative Rules; IL-700-T effective January 1, 2026 (R-12/25). Supplies: employer may withhold at the 4.95% rate in effect on the payment date.

Indiana

• Departmental Notice #1 (R47 / 10-26) — Indiana Department of Revenue; Effective Oct. 1, 2026. Supplies: bonus checks withheld without exemptions; 2.95% state rate for 2026; county rates.

Iowa

• Iowa Withholding Tax Information (Supplemental Wages) and Iowa Withholding Formula effective January 1, 2026 — Iowa Department of Revenue; Formula released November 2025. Supplies: 3.8% when federal tax is withheld at a flat rate.

Kansas

• KW-100 Guide to Kansas Withholding Tax — Kansas Department of Revenue; Tables for wages paid on and after July 1, 2024 (Rev. 10-24). Supplies: 5% when federal is withheld at a flat percentage; otherwise the Kansas formula.

Kentucky

• Employer Payroll Withholding page and 2026 Withholding Tax Calculator — Kentucky Department of Revenue; Tax year 2026. Supplies: 3.5% rate for 2026 and the formula ((wages × periods) − $3,360) × 3.5%.

Louisiana

• Individual Income Tax — Determination of Tax — Louisiana Department of Revenue; Tax years 2025 and after. Supplies: flat 3% income tax rate (used as an estimate; no current withholding table could be verified).
• Louisiana Withholding Tax Tables (page updated November 07, 2024) — Louisiana Department of Revenue; Links only a 2018 emergency rule. Supplies: evidence that no post-2025 withholding table is published on the page.

Maine

• 2026 Withholding Tables for Individual Income Tax (revised August 2026) — Maine Revenue Services; Revised August 2026. Supplies: optional flat 5% on separately paid supplemental wages.

Maryland

• Maryland Employer Withholding Guide (effective January 2026) — Comptroller of Maryland; Effective January 2026. Supplies: annual bonus withheld at 6.50% state rate plus the highest local rate; combined percentages 8.75%–9.80%.
• Withholding Tax Facts 2026 (COM RAD 098) — Comptroller of Maryland; Revised 12/25. Supplies: 2026 local income tax rates for the 23 counties and Baltimore City.

Massachusetts

• Massachusetts Circular M: Income Tax Withholding Tables at 5.0% Effective January 1, 2026 — Massachusetts Department of Revenue; Rev. 12/25 (read through a headless browser; mass.gov blocks plain HTTP clients) (retrieved via browser or archive). Supplies: 5% on bonuses, 9% on the portion above $1,107,750 (4% surtax); exemption factors.

Michigan

• Form 446, 2026 Michigan Income Tax Withholding Guide — Michigan Department of Treasury; 2026. Supplies: separately paid bonuses × 4.25% with no exemptions.

Minnesota

• 2026 Minnesota Withholding Tax Instructions and Tables — Minnesota Department of Revenue; 2026. Supplies: 6.25% on supplemental payments made separately.

Mississippi

• Pub 89-700 Withholding Income Tax Tables and Employer Instructions; Computer Payroll Accounting flowchart for periods in 2026 — Mississippi Department of Revenue; Pub 89-700-25-1 revised 1/13/2026; flowchart revised 8/13/25. Supplies: aggregate method; 4.0% above $10,000 of annualized taxable income; standard deductions.

Missouri

• 2026 Missouri Withholding Tax Formula — Missouri Department of Revenue; 2026. Supplies: optional flat 4.7% on separately paid supplemental wages.

Montana

• Montana Employer and Information Agent Guide with Montana Withholding Tax Tables – 2026 — Montana Department of Revenue; 2026. Supplies: optional flat 5% on separately paid supplemental wages.

Nebraska

• 2026 Nebraska Circular EN — Nebraska Department of Revenue; Paid on or after January 1, 2026. Supplies: optional flat 3.5% on supplemental wages (2026).
• 2027 Nebraska Circular EN — Nebraska Department of Revenue; Paid on or after January 1, 2027 (Rev. 8-2026). Supplies: optional flat 3.5% on supplemental wages (2027).

Nevada

• Nevada Constitution, Article 10, Section 1(9) — Nevada Legislature; Current text. Supplies: "No income tax shall be levied upon the wages or personal income of natural persons.".

New Hampshire

• Interest & Dividends Tax — New Hampshire Department of Revenue Administration; Internet Archive copy of 2026-09-20 (live site blocks automated clients) (retrieved via browser or archive). Supplies: I&D tax repealed for taxable periods beginning after December 31, 2024; it never applied to wages.

New Jersey

• NJ-WT New Jersey Income Tax Withholding Instructions — New Jersey Division of Taxation; September 2025. Supplies: separately paid supplemental wages withheld without exemption allowances; Rate A/B selection.
• Tables for Percentage Method of Withholding — New Jersey Division of Taxation; Wages paid on and after October 1, 2020. Supplies: Rate A and Rate B percentage tables by payroll period.
• Annual rate, wage, base week, and benefit information — New Jersey Department of Labor and Workforce Development; Worker rates January 1–December 31, 2026. Supplies: worker UI 0.3825%, WF/SWF 0.0425%, TDI 0.19%, FLI 0.23%; 2026 wage bases $44,800 and $171,100.

New Mexico

• FYI-104 New Mexico Withholding Tax (Effective January 1, 2026) — New Mexico Taxation and Revenue Department; REV. 11/2025. Supplies: flat 5.9% when federal uses a flat percent; otherwise the annual tables.

New York

• NYS-50-T-NYS New York State Withholding Tax Tables and Methods — New York State Department of Taxation and Finance; (1/26), effective January 1, 2026. Supplies: New York State supplemental rate 11.70%.
• NYS-50-T-NYC New York City Withholding Tax Tables and Methods — New York State Department of Taxation and Finance; (1/26). Supplies: New York City supplemental rate 4.25%.
• NYS-50-T-Y Yonkers Withholding Tax Tables and Methods — New York State Department of Taxation and Finance; Effective January 1, 2026. Supplies: Yonkers supplemental rates: resident 1.95975%, nonresident 0.50%.
• Paid Family Leave: Updates for 2026 — New York State Paid Family Leave; 2026 (read via the Internet Archive copy of 2026-09-30; the live site blocks automated clients) (retrieved via browser or archive). Supplies: employee contribution 0.432% of gross wages, annual maximum $411.91.

North Carolina

• NC-30 Income Tax Withholding Tables and Instructions for Employers (2026) — North Carolina Department of Revenue; 2026. Supplies: flat 4.09% on supplemental wages; 3.99% 2026 rate.

North Dakota

• North Dakota Income Tax Withholding Rates and Instructions — 2026 Calendar Year — North Dakota Office of State Tax Commissioner; 28216 12/2025. Supplies: Option 1: supplemental wages × 1.50%.

Ohio

• Ohio Adm. Code 5703-7-10 and Ohio Rev. Code 5747.02(A)(3) — Ohio Department of Taxation / Ohio Legislative Service Commission; Rule effective January 1, 2026; statute rate for 2026 and thereafter. Supplies: supplemental compensation withheld at the highest rate (2.75%).

Oklahoma

• 2026 Oklahoma Income Tax Withholding Tables (Packet OW-2) — Oklahoma Tax Commission; Effective January 1, 2026 (Revised 11-2025). Supplies: percentage formula, $1,000 allowance and annual tables (no separate supplemental rate).

Oregon

• Oregon Withholding Tax Formulas (150-206-436), Effective January 1, 2026 — Oregon Department of Revenue; 2026. Supplies: optional 8% flat rate on supplemental wages paid apart from the regular payday.

Pennsylvania

• REV-415 Employer Withholding Information Guide — Pennsylvania Department of Revenue; REV-415 (SU) 01-23. Supplies: 3.07% on all compensation including bonuses; employee 401(k) deferrals are taxable.

Rhode Island

• 2026 Rhode Island Withholding Tax Booklet — Rhode Island Division of Taxation; 2026. Supplies: supplemental withholding rate 5.99%.

South Carolina

• WH-1603F Formula for Computing South Carolina 2026 Withholding Tax — South Carolina Department of Revenue; Rev. 11/4/25. Supplies: annualized formula: $5,000 allowances, 10% standard deduction up to $7,500, 0%/3%/6% brackets.

South Dakota

• South Dakota Taxes for Individuals — South Dakota Department of Revenue; Read 2026-10-05. Supplies: South Dakota does not impose a state income tax.

Tennessee

• Hall Income Tax — Tennessee Department of Revenue; Read 2026-10-05. Supplies: Hall income tax repealed for tax periods beginning on or after January 1, 2021 (it never applied to wages).

Texas

• Texas Constitution, Article 8, Section 24-a — Texas Legislature; Current text. Supplies: the legislature may not impose a tax on the net incomes of individuals.

Utah

• Publication 14, Withholding Tax Guide (Rev. 4/26) — Utah State Tax Commission; Pay periods beginning on or after June 1, 2026. Supplies: 4.45% with base allowance phased out at 1.3%.

Vermont

• GB-1210 2026 Income Tax Withholding Instructions, Tables, and Charts — Vermont Department of Taxes; 2026. Supplies: nonperiodic payments estimated at 30% of federal withholding.

Virginia

• Employer Withholding Instructions — Virginia Department of Taxation; Rev. 05/25. Supplies: optional flat 5.75% on supplemental wages.

Washington

• Capital gains tax — Washington State Department of Revenue; Read 2026-10-05. Supplies: Washington's 7% tax applies to long-term capital assets, not wages.
• WA Cares Fund — Employers — Washington State Department of Social and Health Services / ESD; Read 2026-10-05. Supplies: employee premium 0.58% of gross wages, not capped.

West Virginia

• IT-100.2.A Tables for Percentage Method of Withholding — West Virginia Tax Division; March 2026. Supplies: $2,000 exemption; two-earner and optional one-earner annual tables (2.11%–4.58%).

Wisconsin

• Publication W-166 Withholding Tax Guide — Wisconsin Department of Revenue; (1/26). Supplies: approved flat percentages for supplemental payments by annual gross salary: 3.54%, 4.65%, 5.30%, 7.65%.

Wyoming

• Wyoming Department of Revenue — Wyoming Department of Revenue; Read 2026-10-05. Supplies: divisions are Excise, Mineral and Property tax — Wyoming administers no individual income tax.