Capital Gains Tax Estimator
When you sell an investment for a profit, the federal tax you owe depends on two things: how long you held the asset and your total income. Long-term gains — on assets held more than one year — are taxed at preferential rates of 0%, 15%, or 20%, depending on your income bracket, while short-term gains on assets held one year or less are taxed at your ordinary income rate, which can be far higher. This estimator applies the progressive 2026 federal brackets to your capital gain on top of your other income, giving a more accurate estimate than a flat-rate calculation that ignores your bracket. Enter your taxable income excluding the gain, the size of your capital gain, your filing status, and whether the gain is long-term or short-term, and the estimator shows your estimated federal tax, your effective rate on the gain, and your after-tax proceeds. The distinction between short-term and long-term is one of the most important in tax planning: holding an asset just over one year instead of just under can cut the federal rate on the gain from as high as 37% to as low as 0% or 15%, a difference that on a large gain can run into thousands or tens of thousands of dollars. The estimator excludes state capital gains taxes — most states tax gains as ordinary income, so add your state's rate separately — and the 3.8% Net Investment Income Tax that applies to high earners above $200,000 (single) or $250,000 (married) of modified adjusted gross income. Use it to time sales across tax years, to decide whether to harvest losses to offset a gain, or to compare the after-tax outcome of selling now versus holding longer. It is an estimate, not a substitute for a tax professional's analysis of your full situation, but it makes the bracket mechanics visible so you can plan rather than guess.
Capital Gains Tax Estimator
Estimate federal capital gains tax using progressive 2026 brackets.
Estimated federal tax
$7,500
Effective rate 15%
Total capital gain
$50,000
After-tax proceeds
$92,500
Uses 2026 federal brackets. Excludes state taxes, the 3.8% Net Investment Income Tax, and the standard deduction. Long-term gains enjoy lower rates than short-term gains, which are taxed as ordinary income.
How to Use This Calculator
- 1Enter your taxable income excluding the capital gain.
- 2Enter the size of your capital gain.
- 3Select your filing status.
- 4Select whether the gain is long-term or short-term.
- 5Read your estimated federal tax and effective rate.
Why It Helps
- ✓Uses progressive brackets, not a flat rate.
- ✓Distinguishes short-term from long-term gains.
- ✓Helps you time sales to minimize tax.
- ✓Estimates after-tax proceeds for planning.
About This Calculator
When you sell an investment for a profit, the federal tax you owe depends on two things: how long you held the asset and your total income. Long-term gains — on assets held more than one year — are taxed at preferential rates of 0%, 15%, or 20%, depending on your income bracket, while short-term gains on assets held one year or less are taxed at your ordinary income rate, which can be far higher. This estimator applies the progressive 2026 federal brackets to your capital gain on top of your other income, giving a more accurate estimate than a flat-rate calculation that ignores your bracket. Enter your taxable income excluding the gain, the size of your capital gain, your filing status, and whether the gain is long-term or short-term, and the estimator shows your estimated federal tax, your effective rate on the gain, and your after-tax proceeds. The distinction between short-term and long-term is one of the most important in tax planning: holding an asset just over one year instead of just under can cut the federal rate on the gain from as high as 37% to as low as 0% or 15%, a difference that on a large gain can run into thousands or tens of thousands of dollars. The estimator excludes state capital gains taxes — most states tax gains as ordinary income, so add your state's rate separately — and the 3.8% Net Investment Income Tax that applies to high earners above $200,000 (single) or $250,000 (married) of modified adjusted gross income. Use it to time sales across tax years, to decide whether to harvest losses to offset a gain, or to compare the after-tax outcome of selling now versus holding longer. It is an estimate, not a substitute for a tax professional's analysis of your full situation, but it makes the bracket mechanics visible so you can plan rather than guess.
Disclaimer: This calculator provides estimates for educational purposes only and does not constitute financial, tax, or investment advice. Results depend on assumptions that may not reflect your actual situation.
Frequently Asked Questions
How is this different from the basic capital gains calculator?
This estimator applies the progressive 0/15/20% brackets to your gain on top of your other income, giving a more precise estimate than a single flat rate.
Does it include the Net Investment Income Tax?
No. High earners may also owe the 3.8% NIIT. Add that separately if your modified AGI exceeds $250,000 (single) or $200,000.
Does it include state capital gains taxes?
No. Most states tax capital gains as ordinary income. Check your state's rate and add it.
What is the holding period for long-term gains?
More than one year. Assets held one year or less are short-term and taxed at ordinary income rates.
Can I offset gains with losses?
Yes. Capital losses offset gains dollar for dollar. Harvesting losses can reduce or eliminate your taxable gain.
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Written by
James MitchellSenior Financial Analyst & Personal Finance Expert
Certified Financial Planner (CFP) • MBA in Finance, University of Chicago Booth School of Business