What this federal income tax percentage calculator does
The federal income tax percentage calculator takes your taxable income and filing status, walks it through the official IRS 2025 brackets, and tells you exactly how much you owe — plus the two percentages that get confused the most: your effective rate (total tax divided by total income) and your marginal bracket (the rate on your next dollar). It also shows the full per-bracket breakdown so you can see how the progressive system actually works.
Marginal vs. effective rate (the most-googled tax question)
It is genuinely the number-one tax confusion. People hear "I'm in the 24% bracket" and assume the IRS takes 24% of everything they earn. It doesn't. The US system is progressive: each slice of income is taxed only at its bracket's rate. Your first dollars are taxed at 10%, the next chunk at 12%, then 22%, and so on. The 24% you hear about is just the rate on the last slice that sticks out of the next-highest bracket.
That is why your effective rate — total tax owed ÷ total taxable income — is always lower than your marginal bracket. A single filer with $75,000 of taxable income is in the 22% marginal bracket but pays an effective rate closer to 15%, because most of their income is taxed at 10% and 12%.
How federal tax brackets work, step by step
For 2025, a single filer's brackets are 10%, 12%, 22%, 24%, 32%, 35% and 37%. The thresholds are roughly doubled for married filing jointly and head-of-household has its own table. To compute the tax:
- Find your filing status's brackets.
- For each bracket, multiply only the income inside it by that bracket's rate.
- Add up the per-bracket taxes — that's your total federal income tax.
- Divide that total by your taxable income to get the effective rate.
That is exactly what the calculator does on the right, and the table above shows the per-bracket figures so you can audit the math yourself.
What this calculator does not include
To stay focused and accurate, the tool estimates federal income tax only. It does not include FICA payroll taxes (Social Security 6.2% + Medicare 1.45%), state or local income tax, the Alternative Minimum Tax, tax credits (EITC, child tax credit, education credits), or self-employment tax. Those can move your real bill by thousands of dollars in either direction — sometimes downward thanks to credits. Treat the result as a clean starting point, not a finished return.
Tax year used
The figures here are the IRS 2025 brackets (inflation-adjusted in Revenue Procedure 2024-40), for returns filed in 2026. We update this page when the IRS publishes new tables, usually in the autumn before the new tax year begins.
Use with other tools
Pair this estimate with our percent off calculator for shopping and the percentage calculator for everyday rate and discount maths.