Capital Gains Tax Calculator

The line is exactly one year. If you hold the asset for 12 months or less before selling, the IRS treats the profit as a short-term capital gain and taxes it at your ordinary income rate, which can be as high as 37% federally for 2026. Hold the same asset for at least 12 months and a day, and the gain qualifies for long-term capital gains rates of 0%, 15%, or 20%, often half (or less) of what you would pay on a short-term gain. The clock starts the day after you acquire the asset and stops the day you sell, so 'one year and a day' is the practical break-even. Holding period is per lot, not per ticker, so partial sales follow first-in-first-out unless you specify a different lot at the broker.

Long-term capital gains use three brackets in 2026. For single filers, gains up to $48,350 of total taxable income are taxed at 0%, gains in the $48,351 to $533,400 range are taxed at 15%, and gains above $533,400 are taxed at 20%. For married filing jointly, the thresholds are $96,700 (0%), $96,701 to $600,050 (15%), and above $600,050 (20%). Head of household sits in between at $64,750 and $566,700. The brackets are based on your total taxable income including the gain, so a long-term gain can be split across two brackets if it straddles a threshold. Short-term gains use the regular 2026 ordinary income brackets (10%, 12%, 22%, 24%, 32%, 35%, 37%) just like wages.

Almost every state treats capital gains as ordinary income and taxes them at the same rate as wages, which means no special long-term break at the state level. California is the prime example, with a top rate of 13.3% on capital gains for high earners. Nine states have no state income tax at all (Florida, Texas, Washington, Nevada, Tennessee, South Dakota, Wyoming, Alaska, and New Hampshire from 2025 onward), so you owe only federal capital gains tax there. A handful of states offer a partial exclusion: Wisconsin excludes 30% of long-term gains, New Mexico has a 40% deduction, and Washington imposes a 7% tax on long-term gains above $270,000. This calculator uses a flat state rate you enter, so use your state's marginal income tax rate as a reasonable default for most states.

If you sell a security at a loss and buy 'substantially identical' shares within 30 days before or after the sale (a 61-day window centered on the sale date), the IRS disallows the loss for the current tax year under the wash sale rule (IRC Section 1091). The disallowed loss is not gone forever: it gets added to the cost basis of the replacement shares, so you eventually claim it when you sell those without a wash. The rule covers your spouse's accounts and your IRAs as well, so selling SPY in your taxable account and buying it in your Roth IRA within 30 days still triggers a wash. Cryptocurrency is currently exempt because the IRS classifies it as property, not a security, though proposed legislation would close that gap. To safely harvest a loss, wait 31 days before repurchasing or buy a non-substantially-identical fund (for example, swap an S&P 500 ETF for a total market ETF).

The Net Investment Income Tax (NIIT) is an additional 3.8% federal tax on investment income, including capital gains, dividends, interest, and rental income, that applies on top of regular capital gains tax. It kicks in once your modified adjusted gross income (MAGI) exceeds $200,000 for single filers, $250,000 for married filing jointly, or $125,000 for married filing separately. The tax applies to the smaller of your net investment income or the amount your MAGI exceeds the threshold, so a high earner with a large long-term gain pays 23.8% federal (20% LTCG plus 3.8% NIIT) on the portion above the threshold. The thresholds are not indexed for inflation, so the NIIT catches more taxpayers every year. This calculator does not include NIIT; if your income approaches these levels, add 3.8% to the headline federal rate as a rough adjustment.