7
Federal tax brackets (2025)
$14,600
Standard deduction, single filer (2025)
7.65%
FICA rate paid by employee
37%
Top marginal federal rate
How progressive tax brackets work
The US uses a progressive (marginal) tax system. Your income is divided into layers, and each layer is taxed at the rate assigned to that bracket. For a single filer in 2025, the first $11,925 of taxable income is taxed at 10%, the next slice up to $48,475 at 12%, and so on up to 37%. Only the dollars in each bracket are taxed at that bracket's rate — never all your income.
Your taxable income is not your gross income. You first subtract your standard deduction ($14,600 for single filers in 2025 or $29,200 for married filing jointly) or your itemized deductions, whichever is larger. Pre-tax 401(k) contributions and HSA contributions also reduce taxable income before the brackets apply.
Marginal vs. effective tax rate
Your marginal rate is the rate on your last dollar of income — useful for evaluating whether additional income or deductions are worth pursuing. Your effective rate is total tax divided by gross income — the true percentage of your earnings that goes to federal tax. Most middle-income households have effective federal rates of 10–18%, well below their marginal bracket.
What FICA withholding is
- Social Security tax: 6.2% on wages up to the annual wage base ($176,100 in 2025)
- Medicare tax: 1.45% on all wages, no cap
- Additional Medicare: 0.9% on wages over $200,000 (single) or $250,000 (MFJ) — paid at tax time if not withheld
- Your employer matches your Social Security and Medicare contributions dollar for dollar
How to use the income tax calculator
- Enter your gross annual income from all sources
- Select your filing status — this determines bracket thresholds and standard deduction
- Choose your state to include state income tax
- Enter pre-tax deductions like 401(k) contributions to see their tax impact
- Choose standard or itemized deduction
- Review your federal tax, state tax, FICA, effective rate, and estimated take-home pay
💡 Tax year matters
Always check which tax year you're calculating for. Brackets and deductions are adjusted for inflation each year. The 2025 standard deduction is $1,500 higher than 2024's for a single filer — that's real money.
Common mistakes to avoid
- Confusing marginal and effective rates — your bracket is not what you pay on all income
- Forgetting FICA — employees pay 7.65% in addition to income tax
- Ignoring state income tax — rates range from 0% (TX, FL, WA) to over 13% (CA)
- Not accounting for pre-tax benefits that reduce your taxable income
- Assuming a refund is good — it means you gave the government an interest-free loan
Related calculators
Use the Take-Home Pay Calculator to see your paycheck-by-paycheck breakdown after all withholdings. If you work for yourself, the Self-Employment Tax Calculator accounts for the employer half of FICA you now pay directly. And use the W-4 Withholding Calculator to adjust your paycheck withholding and avoid a big year-end bill.