Tax Bracket Estimator

Estimates US federal income tax for the 2024 tax year (filed in 2025) by applying marginal brackets to taxable income. Filing statuses supported: single, married filing jointly, married filing separately, head of household. Standard deduction is applied unless overridden.

Output shows tax owed at each bracket, total tax, effective tax rate, and marginal rate. State tax, FICA, AMT, and credits are not modeled; this is a federal-bracket estimate only.

The US federal income tax is progressive: rates increase as income rises, but each rate applies only to the portion of income within that bracket. A common confusion is the belief that crossing a bracket means all income gets taxed at the higher rate; the correct interpretation is that only the income above the threshold faces the higher rate. The marginal-effective gap reflects this: someone in the 24% bracket has a marginal rate of 24% (the rate on the next dollar) but an effective rate around 14–18% (total tax divided by total income).

The 2024 single-filer brackets: 10% up to $11,600, 12% to $47,150, 22% to $100,525, 24% to $191,950, 32% to $243,725, 35% to $609,350, 37% above. Married-filing-jointly brackets are roughly double those thresholds. The standard deduction in 2024 is $14,600 for single filers and $29,200 for joint filers, subtracted from gross income before applying brackets.

A worked example for a single filer with $80,000 gross income, no other adjustments. Standard deduction reduces to $65,400 taxable income. Tax: 10% × $11,600 = $1,160; 12% × ($47,150 − $11,600) = $4,266; 22% × ($65,400 − $47,150) = $4,015. Total federal income tax: $9,441. Effective rate: 11.8% on gross, 14.4% on taxable income. Marginal rate: 22%. Adding state tax (varies by state, 0–13%) and FICA (7.65% on the first $168,600) brings the all-in tax burden closer to 25–30%.

The TCJA brackets in effect from 2018 through 2025 are scheduled to sunset in 2026 absent legislative action, reverting to pre-TCJA rates with different breakpoints. The estimator updates annually; using the wrong year's brackets produces meaningfully wrong numbers.

Limitations are substantial enough that the estimator should not be used for filing. It excludes credits (Child Tax Credit, Earned Income Credit, retirement savings contribution credit), Alternative Minimum Tax (which can apply to high earners with many deductions), the Net Investment Income Tax (3.8% on investment income above thresholds), and the Additional Medicare Tax (0.9% above $200,000 single). State tax varies wildly; California's top rate of 13.3% applies above $1M while seven states have no income tax. Final filing requires either tax software (TurboTax, FreeTaxUSA, IRS Free File) or a preparer; the estimator is suitable for paycheck planning and rough scenario analysis only.