Capital Gains Tax Calculator

Capital gains tax is the tax you owe on the profit earned when you sell a capital asset — such as stocks, bonds, mutual funds, real estate, or cryptocurrency — for more than you paid for it. The amount you originally paid is called your cost basis, and the profit above that basis is your capital gain. If the asset declined in value, the resulting capital loss can often offset other gains.

The US tax code treats capital gains differently depending on how long you held the asset. Short-term capital gains apply to assets held for one year or less and are taxed at the same ordinary income tax rates as wages — up to 37% in 2025. Long-term capital gains apply to assets held for more than one year and are taxed at preferential rates of 0%, 15%, or 20%, depending on your total taxable income and filing status.

High-income investors may also owe an additional 3.8% Net Investment Income Tax (NIIT) on long-term gains once income exceeds $200,000 (single) or $250,000 (married filing jointly). This calculator accounts for NIIT to give you a complete picture of your total tax liability on investment sales.

1. Enter the original purchase price (cost basis) of your investment.
2. Enter the sale price you received or plan to receive.
3. Add any selling costs such as broker commissions or transaction fees.
4. Enter the holding period in months — this determines short-term vs. long-term treatment.
5. Select your filing status and enter your other taxable income so the calculator can place your gain in the correct rate tier.
6. Review the capital gain or loss, tax amount, NIIT surcharge, and net profit after all taxes.

• Hold assets for more than one year: The single most impactful move is converting a short-term gain (taxed as ordinary income) into a long-term gain by waiting past the 12-month mark before selling.
• Tax-loss harvesting: Selling losing positions before year-end offsets capital gains dollar for dollar, reducing your overall tax bill. Up to $3,000 of net losses can also offset ordinary income annually.
• Use tax-advantaged accounts: Holding growth assets in Roth IRAs or 401(k)s defers or eliminates capital gains taxes entirely on appreciation within those accounts.
• Consider the 0% long-term rate: If your total income is below approximately $48,350 (single) or $96,700 (married) in 2025, your long-term capital gains may be taxed at 0%.
• Opportunity Zone investments: Reinvesting capital gains into Qualified Opportunity Zone funds can defer and potentially reduce taxable gains.
• Gift appreciated assets: Donating appreciated stock to charity avoids capital gains tax and provides a deduction for the full fair market value.