How federal income tax brackets actually work
Federal income tax is marginal, not flat — this is the single most misunderstood part of how US taxes work. Being "in the 22% bracket" doesn't mean 22% of your entire income goes to tax. It means only the portion of your income that falls within that bracket's range is taxed at 22%; the income below it was already taxed at the lower rates (10%, then 12%) that apply to those lower ranges first. Every dollar moves up through the brackets in sequence, each taxed at the rate for its own slice, not the whole amount taxed at whatever rate the top dollar happens to reach.
This is why your effective tax rate — total tax divided by total income — is always lower than your marginal rate, often substantially so. A single filer with $85,000 of gross income in 2026, after the $16,100 standard deduction, has $68,900 of taxable income. That income touches the 10%, 12%, and 22% brackets, but works out to $9,870 in total tax — an effective rate of about 11.6%, well below the 22% marginal rate that applies to their last dollar earned. This calculator shows both numbers, plus a full bracket-by-bracket breakdown, so you can see exactly which dollars were taxed at which rate.
The standard deduction is the amount subtracted from gross income before any tax brackets apply at all — for 2026, that's $16,100 for single filers, $32,200 for married couples filing jointly, and $24,150 for head of household. Nearly all filers use the standard deduction rather than itemizing, since itemizing only makes sense if your specific deductible expenses (mortgage interest, large charitable donations, certain medical costs) exceed that standard amount.
This calculator covers federal income tax only. It does not include state income tax (which varies enormously by state, from 0% to over 13%), FICA payroll tax (Social Security and Medicare, which are calculated separately from income tax), or tax credits, which can reduce your final bill further. Treat this as a starting-point estimate for federal tax specifically, not a complete picture of total tax liability.