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 $49,450 of total taxable income are taxed at 0%, gains in the $49,451 to $545,500 range are taxed at 15%, and gains above $545,500 are taxed at 20%. For married filing jointly, the thresholds are $98,900 (0%), $98,901 to $613,700 (15%), and above $613,700 (20%). Married filing separately uses $49,450 and $306,850. Head of household sits in between at $66,200 and $579,600. 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.

State treatment varies. Some states tax gains through their general income tax, some offer exclusions or deductions, and some without a broad wage income tax can still tax particular capital gains. Washington is an example, so it should not be treated as a universal no-capital-gains-tax state. The calculator accepts one flat rate and cannot apply state-specific exemptions, sourcing, brackets, or local tax.

IRC Section 1091 can disallow a loss when you sell stock or securities and acquire substantially identical stock or securities within 30 days before or after the sale. The replacement transaction can occur in another account, and special basis rules apply. Digital-asset treatment depends on whether the asset is stock or a security for this purpose, so do not apply a blanket crypto exemption. This calculator does not determine whether two investments are substantially identical or whether a transaction is covered. Confirm the current tax treatment before trading.

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.