How your income is taxed, bracket by bracket.

How progressive brackets actually work

The federal income tax is progressive, not flat. Taxable income is stacked from the bottom up, and each slice of income is taxed only at the rate for the bracket that slice falls in. The critical implication, and the source of the most common tax misconception, is that entering a higher bracket does not tax all prior income at the higher rate. Only the dollars above the bracket threshold are taxed at the new rate. A raise that crosses a bracket boundary always increases take-home pay.

Marginal rate versus effective rate

Two rates come out of the same tax calculation and answer different questions. The marginal rate is the rate the next dollar of income would be taxed at, which is the top bracket reached. The effective rate is total tax divided by total taxable income, which blends every bracket the income passes through. Effective rate is the number that leaves the household; marginal rate is the number that drives decisions at the margin. Any incremental question, whether to defer income into a 401(k), whether to do a Roth conversion, whether to accelerate a deduction, is answered with the marginal rate, not the effective rate.

Taxable income is not gross income

The brackets in this calculator apply to taxable income, which is gross income minus adjustments (above-the-line deductions such as HSA and traditional retirement plan contributions), minus either the standard deduction or itemized deductions, minus the qualified business income deduction if applicable. For 2025 the standard deduction is $15,000 for single filers, $30,000 for married filing jointly, $15,000 for married filing separately, and $22,500 for head of household. Enter taxable income (line 15 of Form 1040), not W-2 wages or AGI.

How this differs from capital gains rates

Long-term capital gains and qualified dividends are taxed on a separate rate schedule (0, 15, and 20 percent) that stacks on top of ordinary income. A household with modest ordinary income and a large long-term gain may pay 0 percent on part of the gain even while their ordinary income lands in the 22 percent bracket. Short-term capital gains, in contrast, are taxed as ordinary income at the rates in this tool. The capital gains calculator handles the stacked interaction and the 3.8 percent net investment income tax layered on top.

Why bracket awareness drives Roth conversions

Roth conversion strategy is almost entirely a bracket-arbitrage decision. Converting during a low-income year, an early retirement gap year before Social Security and required minimum distributions begin, or a year with unusual deductions fills up low brackets on purpose to avoid higher brackets later. The rule of thumb is straightforward: pay tax now at a rate below the expected withdrawal rate. Executing on that rule requires knowing where the current marginal rate sits and how much room remains in each bracket before the next one triggers.

Income-timing decisions that use brackets

Beyond Roth conversions, bracket awareness drives a family of planning moves: bunching itemized deductions into alternate years to clear the standard deduction, harvesting capital losses in high-income years and capital gains in low-income years, accelerating self-employment expenses to compress taxable income under a bracket boundary, and timing IRA rollovers or pension elections to sit inside a favorable bracket. Bracket boundaries also interact with income-based phaseouts (IRMAA, ACA credits, the QBI deduction) that introduce real marginal cliffs above and beyond the bracket schedule.

What the calculator does not model

This tool reflects federal ordinary income tax only. It does not model state income tax (rates and structures vary widely), the alternative minimum tax, self-employment tax, additional Medicare tax on wages, net investment income tax, or credits such as the Child Tax Credit or foreign tax credit. For a full-picture projection combine this output with the capital gains calculator and, if Medicare-age, the IRMAA calculator.