What the income tax calculator does
The income tax calculator estimates how much US federal income tax you'll owe. Enter your gross income, pick your filing status and choose whether to use the standard deduction or itemize. The tool subtracts your deduction to get taxable income, walks that figure through the IRS 2025 brackets, and shows the full bracket-by-bracket breakdown — plus your effective and marginal rates, and your after-tax income.
The math, step by step
- Taxable income = Gross income − Deduction (standard or itemized)
- For each bracket, take only the income that falls inside it and multiply by that rate.
- Sum the per-bracket taxes for your total federal income tax.
- Effective rate = Total tax ÷ Gross income (most people care about this number, not the marginal one).
- Marginal bracket = the rate on your next dollar earned.
Everything updates live as you type, which makes it easy to compare scenarios: filing single vs. married, taking the standard deduction vs. itemizing, or planning a Roth conversion.
Standard vs. itemized deduction (the 2025 numbers)
For 2025, the standard deduction is $15,000 for single filers, $30,000 for married filing jointly, $15,000 for married filing separately, and $22,500 for head of household. You should itemize only if your eligible expenses add up to more than that — primarily mortgage interest, state and local taxes (capped at $10,000), charitable contributions and a handful of medical expenses over 7.5% of AGI. Since the 2017 tax law roughly doubled the standard deduction, the vast majority of US filers (around 90%) take the standard.
Why marginal and effective rates differ
The most-googled tax confusion of all time: hearing "I'm in the 22% bracket" and assuming the IRS takes 22% of everything. 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%, then 12%, then 22%, and so on. That's why your effective rate is always lower than your marginal bracket. A single filer earning $85,000 is in the 22% marginal bracket but pays an effective rate closer to 12% after taking the standard deduction.
What this calculator does not include
To keep the focus tight, the tool estimates federal income tax only. It excludes FICA payroll taxes (Social Security 6.2% + Medicare 1.45%), state and local income tax, the Alternative Minimum Tax, refundable and non-refundable credits (EITC, Child Tax Credit, education credits, etc.) and self-employment tax. Real tax bills can be thousands of dollars lower thanks to credits, so the figure here is your tax before credits — a clean starting estimate, not a finished return.
Use with the other money tools
For percentage-only tax problems, the federal income tax percentage calculator shows just the bracket math. The salary calculator converts between hourly and annual pay so you can plug the right gross into this tool. To grow what's left, try the investment calculator.