Capital Gains Tax Calculator (US) — 2025 Federal + State
Sold a stock, fund, or crypto position and wondering what's left after tax? Drop in the sale price, your cost basis, how long you held it, and your other taxable income. The calculator splits federal capital-gains tax through the 0%/15%/20% bands, adds the 3.8% Net Investment Income Tax where it applies, and tops it with your state rate. Built for the single filer.
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How US capital-gains tax actually works
Holding period decides everything. An asset held a year or less is a short-term capital gain, taxed as ordinary income at your marginal rate (10–37%). Hold for more than a year and the gain becomes long-term, taxed at preferential rates of 0%, 15%, or 20% depending on your total taxable income.
On top of federal tax, two extras may apply. The Net Investment Income Tax (NIIT) adds 3.8% on investment income when your modified AGI exceeds $200,000 (single). State capital-gains tax varies — nine states levy nothing, while California taxes long-term gains at up to 13.3% as ordinary income. This calculator lets you set your state rate manually.
Estimates only. State rules, AMT, qualified small-business stock (QSBS), wash-sale rules, opportunity zones, and high-income phase-outs are not modelled. Talk to a CPA before realising large gains.