Comprehensive Guide
Learn more in our Personal Finance Guide.
How it works
The US federal income tax is progressive: each slice of income is taxed at its own bracket rate, from 10% on the first dollars to 37% on income above the top threshold. The calculator applies the standard deduction first, then runs every dollar through its bracket, summing the tax per band. The two headline numbers are the marginal rate — the tax on your next dollar, which matters for raises and deductions — and the effective rate, your average tax across all income, which is always lower. This estimate covers federal income tax only: state tax, FICA (Social Security and Medicare) and credits such as the child tax credit are separate, so the number is a planning baseline rather than a filing figure. Raising a deduction 'costs' only the marginal rate of the sheltered dollars — the insight behind tax-advantaged retirement accounts. Every field in this calculator exists for a reason. Enter Gross annual income, Deductions (optional), Estimated tax, Income after tax, Effective rate, and the engine recomputes the results instantly — no signup, no email, and nothing is sent to a server, because the math runs entirely in your browser. Change one input at a time to see which lever moves the result most; that sensitivity, not any single number, is usually the real insight. The worked example below the form uses realistic defaults so you can sanity-check the output before trusting it with your own figures, and the formula is published on the page so you can verify every step of the arithmetic yourself.Formula
Tax = Σ (bracket income x bracket rate), applied progressively
Tips
- Use this number for planning, then confirm with tax software — credits and phaseouts shift real liability.
- A raise taxed at your marginal rate is still a raise; compare net, not gross.
- Roth vs pre-tax contributions change future taxes, not this year's estimate directly — model both.
- Re-run after major life events: marriage, a child, a home, or a big raise.
Frequently asked questions
What is the standard deduction for 2026?
The calculator assumes roughly $15,000 for single filers (2026 estimate). If your itemised deductions — mortgage interest, charitable gifts, state and local taxes — exceed the standard deduction, enter your itemised total in the deductions field instead.
What is the difference between marginal and effective tax rate?
Your marginal rate is the tax rate on your next dollar of income (where you sit in the bracket structure). Your effective rate is total tax divided by total income. Because brackets are progressive, the marginal rate is always higher, which is why effective rate is the fair description of 'what you really pay'.
Does the calculator include Social Security and Medicare?
No — FICA is a flat payroll tax separate from income tax. For a full picture of your pay, pair this tool with the Take-Home Pay calculator, which nets out federal, state and FICA.
How do tax credits differ from deductions?
A deduction reduces taxable income (worth your marginal rate per dollar); a credit reduces tax owed dollar-for-dollar. Credits are consequently far more valuable, and the main ones (child tax credit, education credits) are not included in this basic estimate.