What Is the Income Tax Calculator?
An income tax calculator estimates your US federal income tax using progressive brackets. Enter your gross income and filing status to see your taxable income, total tax, effective rate, and the marginal bracket your top dollars fall into.
How to use this calculator
Type your numbers into the fields above. The results change the moment you edit any input, so you can try one scenario after another and see exactly what moves. Most calculators show a short summary of the key figures, a line-by-line breakdown underneath, and — where it applies — a year-by-year schedule you can export to a spreadsheet. Everything runs in your browser; nothing is stored or sent anywhere. Treat the output as a planning estimate, not as final word on a real decision.
The Formula
Tax is computed by subtracting the standard deduction from gross income to get taxable income, then applying each bracket's rate only to the portion of income within it. The effective rate is total tax ÷ gross income; the marginal rate is the top bracket applied.
Worked Example
A single filer earning $75,000 in 2025 has a $15,000 standard deduction, leaving $60,000 taxable. The tax is the sum across the 10%, 12%, and 22% brackets, producing an effective rate well below the top marginal rate.
Tips for the Most Accurate Estimate
- Use the correct filing status — it changes brackets and the deduction.
- Itemizing can beat the standard deduction if your deductions are large.
- Credits reduce tax dollar-for-dollar; deductions reduce taxable income.
- Add state tax separately; this is federal only.
- Round income to the nearest thousand for a quick estimate.
Frequently Asked Questions
Q: What is the difference between marginal and effective rate?
Marginal is the rate on your last dollar of income; effective is your total tax divided by total income. Most people pay an effective rate below their marginal rate.
Q: Does this include my state tax?
No. This estimates federal income tax only. Add your state's tax separately for a complete picture.
Q: Why is my effective rate lower than my bracket?
Because lower portions of income are taxed at lower bracket rates; only the top slice is taxed at your marginal rate.