Capital gains tax calculator
Tell us the taxable income you already have, then the gain, and whether you held it more than a year. We stack the gain on top of that income. The extra 3.8% investment tax is not in here.
Result
Federal tax on the gain
$1,582.50
The extra 3.8% tax on investment income is not in this.
Here’s one
Single, $40,000 of other taxable income, $20,000 long-term gain
Filing single, with $40,000 of other taxable income, the 0% long-term band runs through $49,450. Part of a $20,000 gain can sit in that band and the rest at 15%. Hold it a year or less and it gets taxed like ordinary income instead.
How it works
Long-term gains fill the 0% room first, then 15%, then 20%. Short-term gains are just added to ordinary income, and we show the extra tax that causes.
Where this comes from
Held more than a year, the gain uses the 0%, 15%, and 20% bands. Held a year or less, it is taxed like ordinary income. Topic 409 explains the holding period. The 2026 dollar lines are in Revenue Procedure 2025-32, because the topic page can still be showing last year’s amounts. The extra 3.8% investment tax is not in this result.
Good for
Federal tax on one gain. Get the cost basis, how long you held it, and your state sorted before you trust the number.
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Don’t file a return from this