Capital Gains Tax Calculator: 2026 Federal Rates
This capital gains tax calculator estimates the federal income tax on one sale for tax year 2026. Enter your filing status, your taxable income before the sale, and the sale details, and it shows the tax the gain could add, the effective rate on the gain, and what remains after that tax.
Capital Gains Tax Calculator
Estimated federal tax on the gain
Under these assumptions, a long-term gain of $15,000.00 could add an estimated $2,250.00 of federal income tax for 2026, an effective rate of 15.0% on the gain, leaving about $22,750.00 after fees and that tax.
- Taxable gain
- Effective tax rate on the gain
- After-tax proceeds
- Holding period
- Federal income tax without the sale
- Federal income tax with the sale
How the Gain Is Taxed
| Rate Band | Portion of Gain | Tax |
|---|---|---|
| Long-term rate 15% | $15,000.00 | $2,250.00 |
2026 thresholds for long-term gains and qualified dividends: 0% up to Single $49,450, Married filing jointly $98,900, Married filing separately $49,450, Head of household $66,200; 20% above Single $545,500, Married filing jointly $613,700, Married filing separately $306,850, Head of household $579,600 of taxable income. Source: IRS Rev. Proc. 2025-32.
Assumptions
- Uses 2026 federal income tax brackets and capital gains thresholds from IRS Rev. Proc. 2025-32.
- Long-term gains and qualified dividends are stacked on top of ordinary taxable income; short-term gains are taxed as ordinary income.
- State and local income taxes are excluded.
- The 3.8% Net Investment Income Tax may apply above $200,000 (single or head of household), $250,000 (married filing jointly), or $125,000 (married filing separately) of modified adjusted gross income; it is not included.
- Special 25% (unrecaptured section 1250) and 28% (collectibles and qualified small business stock) gain categories are excluded.
- Capital loss limits, carryovers, and other gains or losses for the year are not modeled.
Educational estimate only. This calculator uses the assumptions you enter to illustrate a possible financial outcome. It does not predict future investment performance, interest rates, inflation, taxes, market prices, or financial results. Actual outcomes may differ.
Tax calculations are simplified estimates for educational purposes and do not replace tax advice. Federal and state rules can change, and individual circumstances vary.
How the Calculator Estimates the Tax
The calculator works out your federal income tax twice, once without the sale and once with it, and reports the difference as the tax on the gain. That approach captures how a gain can push income across a rate threshold.
The gain is sale proceeds minus cost basis minus selling fees and adjustments. How it is taxed depends on how long you held the asset:
- Long-Term Gains: Assets held more than one year are taxed at 0%, 15%, or 20%. The gain is stacked on top of your ordinary taxable income, so some of it can fall in the 0% band and the rest in a higher one.
- Short-Term Gains: Assets held one year or less are taxed as ordinary income at your regular bracket rates, from 10% to 37%.
Qualified dividends share the 0%, 15%, and 20% bands with long-term gains, so the calculator stacks them before the gain when you enter them. Qualified dividends explains which dividends qualify and the holding-period rules behind them.
The 2026 Thresholds Used
The rates and income thresholds come from IRS Revenue Procedure 2025-32, published in Internal Revenue Bulletin 2025-45. For long-term gains and qualified dividends, the 0% rate applies to taxable income up to $49,450 for single filers and married individuals filing separately, $98,900 for married couples filing jointly, and $66,200 for heads of household. The 20% rate begins above $545,500 (single), $613,700 (married filing jointly), $306,850 (married filing separately), and $579,600 (head of household).
As an example, a single filer with $40,000 of other taxable income and a $20,000 long-term gain has $9,450 of the gain in the 0% band and $10,550 in the 15% band. The estimated federal tax on the gain is $1,582.50, a Fin Loom calculation from those thresholds.
What the Calculator Leaves Out
The estimate covers federal income tax on one sale. It does not include:
- State Taxes: Most states tax capital gains, often as ordinary income, and the calculator excludes them.
- Net Investment Income Tax: A 3.8% tax can apply when modified adjusted gross income exceeds $200,000 (single or head of household), $250,000 (married filing jointly), or $125,000 (married filing separately). The calculator flags when your figures cross that level but does not add the tax.
- Special Gain Categories: Unrecaptured section 1250 gain (up to 25%) and collectibles or certain small business stock gain (up to 28%) follow different rules.
- Losses and Netting: Other gains and losses for the year, loss limits, and carryovers are not modeled. A loss shows $0 of tax on this sale.
Reading Your Result
The headline figure is the estimated additional federal tax on the gain. The effective rate divides that tax by the taxable gain, which can sit between two bracket rates when the gain spans a threshold. The breakdown table shows how much of the gain falls in each rate band. After-tax proceeds subtract selling fees and the estimated tax from the sale price.
More Fin Loom Calculators
This tool is part of Fin Loom's set of financial calculators and reference tools, which covers inflation, compound interest, investment growth, dividends, withdrawals, capital gains tax, and stock trades.
Frequently Asked Questions
What Is the Difference Between Short-Term and Long-Term Capital Gains?
Assets held one year or less produce short-term gains taxed at ordinary rates. Assets held more than one year produce long-term gains taxed at 0%, 15%, or 20%.
Does the Calculator Use 2026 Tax Brackets?
Yes. It uses the 2026 ordinary brackets and capital gains thresholds from IRS Rev. Proc. 2025-32, published in Internal Revenue Bulletin 2025-45.
Does the Estimate Include State Tax or the 3.8% NIIT?
No. State taxes are excluded, and the 3.8% Net Investment Income Tax is flagged when your income may reach its threshold but is not added.