Capital Gains Tax Estimator

How this calculator stacks a gain

Enter taxable income after deductions but before the gain entered here, then select the filing status and tax year. The calculator finds the extra federal tax created by adding the gain to that income. It does not multiply the whole gain by the final bracket rate, which would overstate tax whenever a gain crosses a bracket boundary.

Short-term gains (held one year or less) are treated as incremental ordinary income. Long-term gains (held more than one year) fill any remaining 0% long-term-gain band first, then the 15% band, then the 20% band if applicable. The displayed rate is the resulting effective federal tax rate on this gain, not a marginal rate.

2026 long-term capital-gains brackets

These are the default 2026 limits. The calculator also includes 2024 and 2025 tables, so the output remains tied to the selected tax year. IRS long-term-gain thresholds apply after the ordinary taxable income entered in the tool has already occupied its portion of the bands.

Net Investment Income Tax and other exclusions

This estimate excludes the 3.8% Net Investment Income Tax (NIIT), because calculating it requires modified AGI and all net investment income, neither of which this tool collects. It also excludes state tax, the special rules for collectibles and qualified small-business stock, depreciation recapture, primary-residence exclusions, and loss carryforwards.

Wash-sale rule

A loss may be disallowed when you buy a substantially identical security within 30 days before or after its sale. That rule and netting gains against losses can change the gain that belongs in this calculator; determine your net reportable gain before using this single-gain estimate.