Why your tax isn't a flat percentage
US federal income tax is progressive: income is taxed in slices, each at its own rate from 10% up to 37%. Only the dollars inside each bracket are taxed at that bracket's rate. First, the standard deduction (or your itemized total) comes off your income to get taxable income; then the brackets apply.
That's why two people in the same "tax bracket" can pay very different effective rates — deductions and where your income lands in the slices matter more than the headline bracket.
Good to know
Getting a raise into a higher bracket never lowers your take-home — only the dollars above the threshold are taxed at the higher rate.
Common questions
Your marginal rate is the rate on your last dollar (your top bracket). Your effective rate is total tax divided by total income — always lower, because the first dollars are taxed at lower rates.
No. This is federal income tax only. For Social Security and Medicare plus state tax, use the paycheck calculator instead.
It applies the 2026 standard deduction automatically. If you itemize more than that, enter the extra amount in "extra deductions".
The IRS adjusts brackets and the standard deduction for inflation annually, which is why 2026 figures differ from prior years.