Income Tax Calculator

How This Calculator Works

Federal income tax is calculated by applying the marginal tax brackets for your filing status to your taxable income — gross income minus the standard or itemized deduction. Enter your gross annual income, filing status, and any itemized deductions, and this calculator estimates your taxable income, tax owed, effective tax rate, and after-tax income.

This is different from the Paycheck / Salary Calculator, which answers “how much lands in my bank account per paycheck” including FICA payroll taxes. This calculator answers “how much will I owe the IRS for the year,” which is the number that matters for tax planning and comparing scenarios (a raise, a new deduction, a change in filing status).

Filing jointly with a second earner? Open “Filing jointly with a second earner?” and enter their gross income separately — it combines into one household return and is taxed together, the way a real joint return works, rather than requiring you to add the two incomes together yourself first.

What this doesn’t cover: this estimates gross federal tax from income and deductions only — it doesn’t apply tax credits (like the Child Tax Credit or Earned Income Tax Credit), which can further reduce what you actually owe. Credit rules and amounts are specific and change over time, so this calculator doesn’t guess at them — check the current IRS instructions or a tax professional for credits that may apply to your situation.

The Formula

$$\text{Taxable Income} = \vA{\text{Gross Income}} - \vB{\text{Deduction}}$$

where $\vB{\text{Deduction}}$ is the larger of your standard deduction or your itemized deductions — using whichever actually lowers your bill more, matching how a real return is filed:

Federal tax uses the marginal bracket method: each slice of taxable income is taxed at its own bracket’s rate, not your whole income at your top rate. Your effective rate (total tax divided by gross income) is always lower than your marginal rate (the rate on your next dollar earned), since only the income above each threshold is taxed at that threshold’s rate.

Worked Example

A single filer with $\vA{\$85{,}000}$ in gross income, using the standard deduction:

1. Taxable income: $\vA{85{,}000} - \vB{16{,}100} = 68{,}900$ dollars.
2. Tax owed (marginal brackets): $1{,}192.50 + 4{,}386.00 + 4{,}493.50 = 10{,}072$ dollars.
3. Effective tax rate: $10{,}072 \div \vA{85{,}000} = 11.8\%$.
4. After-tax income: $\vA{85{,}000} - 10{,}072 = 74{,}928$ dollars.

Their marginal rate is 22% (the rate on their last dollar earned), even though their effective rate is only about 11.8%.

Common Mistakes

• Confusing marginal rate with effective rate. A “22% tax bracket” doesn’t mean 22% of your whole income goes to tax — only the portion of income that falls within that bracket is taxed at 22%; the effective rate (total tax ÷ total income) is almost always lower.
• Forgetting state income tax entirely. This calculator is federal-only by design (state rates vary too much to estimate honestly) — your real take-home income also depends on your state’s own rate, including the nine states with no state income tax at all.
• Using the wrong filing status. Married filing jointly, married filing separately, and head of household all use different bracket thresholds and standard deductions — picking the wrong one can meaningfully change the result.