Methodology

Every assumption behind the numbers, so you can judge how close the estimate is to your situation.

Federal

Source: IRS Rev. Proc. 2025-32; SSA 2026 contribution and benefit base. Taxable income equals gross wages minus pre-tax retirement contributions, minus Section 125 benefits, minus the standard deduction. The seven brackets are applied progressively. Itemized deductions, the child tax credit, the earned income credit, and all other credits are not modeled.

Social Security and Medicare

Social Security is 6.2% of wages up to 184,500. Medicare is 1.45% of all wages plus 0.9% above the Additional Medicare Tax threshold. Section 125 benefits are excluded from both; retirement deferrals are not.

State

Each state is modeled with its standard deduction, personal exemption where it has a simple one, and its flat rate or bracket schedule. Local income taxes (city, county, school district) are never included. Credits and phase-outs are not modeled. Pennsylvania is treated as taxing retirement contributions because it does.

Data status: 47 of 51 state entries have every figure confirmed against the state revenue department or the Tax Foundation's 2026 tables; 4 have one or more figures still awaiting official publication and are flagged on their pages. Each state page lists its sources, tax year, and confidence level.

What this tool is not

It is not a withholding calculator. Your employer withholds based on your W-4, which can differ substantially from your actual liability. It is not tax advice. For decisions with real money at stake, consult a professional or the official sources linked on each page.

Updates

Parameters are stored in versioned data files and updated when the IRS and each state publish new figures, typically between October and January. Subscribe on any calculator page to be notified.