What is a US Income Tax Calculator?
A US federal income tax calculator estimates your federal tax liability based on your taxable income, filing status, and applicable deductions. It applies the IRS tax brackets for the selected tax year to compute your marginal and effective tax rates.
2025 Federal Tax Brackets (Single Filer)
10%: $0 – $11,925 · 12%: $11,926 – $48,475 · 22%: $48,476 – $103,350
24%: $103,351 – $197,300 · 32%: $197,301 – $250,525 · 35%: $250,526 – $626,350 · 37%: Above $626,350
Standard deduction (2025): $15,000 (single) / $30,000 (married filing jointly)
- Marginal vs effective rate: The top bracket rate is not your effective rate — only income in each bracket is taxed at that rate. A $100,000 income is NOT all taxed at 22%.
- Standard deduction: Most taxpayers take the standard deduction ($15,000 single, $30,000 MFJ) rather than itemising. Itemise only if mortgage interest + property tax + charitable contributions + state taxes exceed the standard deduction.
- SALT cap: The $10,000 cap on State And Local Tax (SALT) deductions (from the 2017 TCJA) limits deductions for high-income earners in high-tax states like California, New York, and New Jersey.
What is the difference between marginal and effective tax rate?
Marginal rate is the rate applied to your last dollar of income — the rate of your highest bracket. Effective rate is total tax paid divided by total income. For a single filer with $80,000 taxable income: tax = $1,192.50 (10%) + $4,413.00 (12%) + $6,931.50 (22%) = $12,537 total. Effective rate = 15.7%, even though the marginal rate is 22%. The marginal rate matters for decisions about earning additional income; the effective rate describes your actual overall tax burden.
How do I reduce my federal income tax legally?
Key strategies: (1) Maximise 401(k)/403(b)/IRA contributions — each $1 in traditional contributions reduces taxable income by $1. (2) Contribute to HSA if on a high-deductible health plan — triple tax benefit. (3) Harvest tax losses in taxable investment accounts to offset capital gains. (4) Bunch deductions into alternate years to exceed the standard deduction threshold. (5) Contribute to a 529 plan (no federal deduction, but many state deductions). (6) Claim all eligible credits — Child Tax Credit, Earned Income Credit, education credits.
What is the AMT (Alternative Minimum Tax)?
The Alternative Minimum Tax is a parallel tax calculation designed to ensure high-income taxpayers pay a minimum amount of tax. You calculate your tax under regular rules, then under AMT rules (which disallow certain deductions and apply a flat 26–28% rate). You pay whichever is higher. The AMT exemption for 2025 is $88,100 (single) / $137,000 (MFJ). After TCJA 2017, far fewer middle-class taxpayers are subject to AMT — it primarily affects those with significant ISO stock option exercises, large state tax deductions, or high income.
Last Updated: March 2026 · For US audiences