Capital Gains Tax Calculator
Estimate federal capital gains tax on an investment sale based on your income, filing status, and holding period.
Important disclaimer
This calculator estimates federal tax only, using 2025 tax brackets, and does not include state capital gains tax. It does not account for capital losses, the qualified small business stock exclusion, or itemized deductions. This is not tax advice — consult a tax professional for your actual filing.
Your Sale Details
Estimated Tax
Tax Owed on Gain (Long-Term)
$3000.00
Effective Rate on Gain
15.00%
Short-Term vs. Long-Term Tax on the Same Gain
How the Capital Gains Tax Calculator Works
This calculator estimates federal tax owed on an investment gain by stacking the gain on top of your other taxable income. Short-term gains (assets held one year or less) are taxed using ordinary income brackets, while long-term gains (held more than one year) use the lower long-term capital gains brackets.
Formula
Tax on the gain = tax on (other taxable income + gain) minus tax on (other taxable income alone), calculated using the applicable progressive bracket table (ordinary brackets for short-term, long-term capital gains brackets for long-term). This 'stacking' method reflects how the IRS actually layers capital gains on top of ordinary income.
Example
A single filer with $80,000 of other taxable income and a $20,000 long-term gain has that gain taxed entirely in the 15% long-term bracket, for about $3,000 in tax, versus a noticeably higher amount if the same gain were short-term and taxed at ordinary rates.
Limitations
This calculator estimates federal tax only and does not include state capital gains tax, which can add a significant amount in many states. It uses 2025 federal tax brackets, which may be adjusted for inflation in later years, and it does not account for every possible adjustment such as capital losses, the qualified small business stock exclusion, or itemized deductions. This is not tax advice; consult a tax professional for your actual filing.
How to use the result responsibly
- Check that every input uses the unit and time period shown beside the field.
- Compare the result with the worked example and formula above.
- For financial, tax, health, or legal decisions, confirm current rules with a qualified professional or the relevant authority.
Frequently Asked Questions
Why is long-term capital gains tax usually lower?
The federal tax code uses separate, generally lower brackets (0%, 15%, and 20%) for gains on assets held more than one year, to encourage longer-term investing, compared to ordinary income brackets that apply to short-term gains.
Does this include state taxes?
No. This calculator only estimates federal capital gains tax. Many states also tax capital gains, often at your regular state income tax rate, so check your state's rules separately.
What is the Net Investment Income Tax?
It is an additional 3.8% federal surtax on investment income, including capital gains, for taxpayers above certain income thresholds ($200,000 for single filers, $250,000 for married filing jointly). This calculator includes it only as an optional toggle.
Editorially reviewed September 22, 2026. Read our calculation methodology and editorial policy.