Capital Gains Tax Calculator

The Capital Gains Tax Calculator estimates the federal tax owed when you sell an investment such as stock, a mutual fund, crypto, or property for more than you paid. It distinguishes between short-term gains, on assets held one year or less and taxed as ordinary income, and long-term gains, on assets held more than a year and taxed at the preferential 0%, 15%, or 20% rates. This holding-period distinction is the single biggest lever in capital gains planning.

To compute the gain, the tool subtracts your cost basis (purchase price plus commissions and any reinvested dividends) from the sale proceeds. Long-term rates are tied to your taxable income and filing status, so the calculator places your gain on top of your ordinary income to determine whether it falls in the 0%, 15%, or 20% band. High earners may also owe the additional 3.8% Net Investment Income Tax, which the tool can factor in.

Investors use this calculator before selling to estimate the after-tax proceeds, to time sales so a holding crosses the one-year mark into long-term treatment, and to plan tax-loss harvesting where realized losses offset realized gains. It complements the Income Tax Calculator for your overall picture and the Tax Bracket Calculator for understanding how a large gain might push part of your income into a higher band.

A useful tip: gains and losses of the same type net against each other first, and up to $3,000 of net capital loss can offset ordinary income each year, with the remainder carried forward. Keep accurate records of your cost basis, including dividend reinvestments, because overstating proceeds or understating basis leads to overpaying. State capital gains taxes are not included in this federal estimate.