Capital Gains Tax Calculator

Capital Gains Tax Calculator

How to Use the Capital Gains Tax Calculator

1. 1

   Choose the holding period

   Select Long-term if you owned the asset for more than one year before selling, or Short-term if you held it one year or less.

2. 2

   Enter the sale

   Type the purchase price (your cost basis), the sale price and any buying and selling costs such as commissions, fees or, for property, closing costs and capital improvements.

3. 3

   Enter your other income

   Pick your filing status and enter your other taxable income for the year, after the standard or itemized deduction, without this sale.

4. 4

   Review the tax and the comparison

   Read the capital gain, regular tax, net investment income tax, total and effective rate, plus what the same gain would cost under the other holding period.

How capital gains tax is calculated

Your gain is the sale price minus your cost basis minus the costs of buying and selling. If you held the asset one year or less, the gain is short-term and is added to your ordinary income, so it is taxed at your regular bracket rates. The calculator finds the tax on your other income with and without the gain and reports the difference.

If you held it more than one year, the gain is long-term. It is stacked on top of your other taxable income, and the part that falls below the 0% breakpoint is tax-free, the next part is taxed at 15% and anything above the upper breakpoint at 20%. The 3.8% net investment income tax (Form 8960) applies to the smaller of your investment income and the amount your modified AGI exceeds $200,000 single or head of household, or $250,000 married filing jointly.

Gain = sale price - purchase price - costs; Short-term tax = tax(other income + gain) - tax(other income); Long-term tax = 0% / 15% / 20% on the gain layered above other income; NIIT = 3.8% x min(gain, MAGI - threshold), with MAGI approximated as other taxable income + gain

Worked examples

• Single filer, $60,000 of other taxable income, shares bought for $10,000 and sold for $25,000: the gain is $15,000. Held more than a year, the whole gain lands in the 15% band (other income is already above $49,450), so tax is $2,250. Held a year or less, it is taxed at 22% for $3,300. Waiting saved $1,050.
• Single filer, $30,000 of other taxable income and a $15,000 long-term gain: taxable income is $45,000, all below the $49,450 breakpoint, so the gain is taxed at 0%. The same gain short-term would cost $1,800.
• Married couple, $240,000 of other taxable income, sells for $100,500 an asset bought for $50,000 with $500 of costs: the gain is $50,000. Long-term tax is 15%, or $7,500. Estimated MAGI of $290,000 is $40,000 over the $250,000 threshold, so NIIT is 3.8% of $40,000, or $1,520. Total $9,020, an effective 18.0% of the gain. Short-term it would be $13,520.

2026 long-term capital gains tax brackets

Breakpoints apply to total taxable income, including the gain (IRS Rev. Proc. 2025-32). Short-term gains use the ordinary brackets, from 10% to 37%.

Legal ways to lower capital gains tax

• Hold for more than one year. Long-term rates are much lower than ordinary rates for most people, as the $3,300 vs $2,250 example shows.
• Harvest losses. Selling investments that are down lets those losses offset your gains. Net losses beyond your gains can offset a limited amount of ordinary income each year (see the Schedule D instructions) and the rest carries forward. Avoid the wash-sale rule: buying the same or a substantially identical security within 30 days before or after the sale disallows the loss.
• Time sales for low-income years. In a gap year, early retirement or a year with a business loss, more of your gain may fit in the 0% band ($49,450 single, $98,900 joint taxable income). Some investors deliberately realize gains then to reset their basis.
• Give appreciated stock to charity instead of cash. If you have held it more than a year, you generally deduct its fair market value when you itemize and never pay tax on the gain. Deductions for gifts of appreciated property are limited to a percentage of AGI.
• Lower your taxable income with pre-tax savings. Contributions to a 401(k) (up to $24,500 in 2026, $32,500 at 50+) or an HSA ($4,400 self-only, $8,750 family) can pull more of a gain into a lower bracket and reduce MAGI for the NIIT.
• Use tax-advantaged accounts for active trading. Gains inside a 401(k) or IRA are not taxed when they occur. Always report every sale: brokers send the IRS Form 1099-B, and leaving gains off your return leads to penalties and interest.

What this calculator simplifies

MAGI for the NIIT is approximated as your other taxable income plus this gain. Real MAGI starts from AGI, before the standard or itemized deduction, so the tool can understate the NIIT when you are near the threshold. It treats this sale as your only investment income and gain for the year, and your other income as fully ordinary.

It does not model collectibles or unrecaptured real estate depreciation, which have their own maximum rates, the home-sale exclusion, depreciation recapture on business property, wash sales, installment sales, Opportunity Zone deferral, the alternative minimum tax or state tax. Married filing separately is not supported. Report actual sales on Form 8949 and Schedule D, and talk to a CPA or enrolled agent before a large sale.

Features

• Gain = sale price minus purchase price minus buying and selling costs
• Short-term gains taxed as ordinary income at your bracket (the extra tax the gain adds)
• Long-term gains taxed at 0%, 15% and 20%, stacked on top of your other taxable income
• Estimates the 3.8% net investment income tax above the MAGI threshold
• Compares short-term vs long-term tax on the same gain
• Table of the 2026 0% / 15% / 20% breakpoints for each filing status

Frequently Asked Questions