How US Federal Tax Brackets Work
The US uses a progressive income tax. Your income is split into slices, and each slice is taxed at its own rate. Moving into a higher bracket only raises the tax on the dollars inside that bracket — never on the income below it. That is why a raise can never reduce your take-home pay through income tax alone.
This calculator uses the 2024 IRS brackets and standard deductions ($14,600 single, $29,200 married filing jointly, $21,900 head of household) to estimate federal income tax, then adds FICA and an approximate state income tax.
Marginal Rate vs. Effective Rate
- Marginal rate: the rate on your last dollar of taxable income. It tells you how much of a raise or bonus goes to federal income tax.
- Effective rate: your total income tax divided by your gross income. It is always lower than the marginal rate and is the better measure of your overall tax burden.
Worked Example: $75,000 Salary, Single Filer
- Taxable income: $75,000 − $14,600 standard deduction = $60,400
- 10% on the first $11,600 = $1,160
- 12% on $11,600–$47,150 = $4,266
- 22% on the remaining $13,250 = $2,915
- Federal income tax ≈ $8,341 — an effective rate of about 11.1%, even though the marginal rate is 22%
What FICA Adds
On top of income tax, employees pay FICA: 6.2% Social Security on wages up to $168,600 in 2024, plus 1.45% Medicare on all wages. For most people that is 7.65% of their paycheck. High earners also owe an additional 0.9% Medicare tax above certain thresholds, which this estimate does not include.
What This Estimate Leaves Out
The calculator assumes the standard deduction and wage income. It does not model itemized deductions, tax credits (such as the Child Tax Credit), capital gains rates, pre-tax retirement contributions, self-employment tax or local taxes, and state figures are simplified. Use it to understand your brackets and plan, and use IRS tools or a tax professional for your actual return.