Estimate 2026 capital gains tax on investment sales using 2026 long-term rate tiers, an ordinary short-term rate, NIIT, and optional state tax.
When you sell an investment for a profit, the IRS taxes the gain. Short-term gains, held one year or less, are taxed at ordinary income rates. Long-term gains, held over one year, use 2026 federal capital gains tiers of 0%, 15%, and 20% based on taxable income. High earners may also owe the 3.8% Net Investment Income Tax (NIIT).
This calculator estimates the tax on a realized gain using the 2026 rate tiers, your filing status, and your taxable income before the sale. Enter your purchase price, sale price, filing status, and existing taxable income to see how much of the gain lands in each federal tier. An optional state tax rate provides a more complete picture.
Tax planning is essential for maximizing after-tax returns. Knowing the estimated tax bill before selling helps you decide whether to hold an asset longer, harvest losses, or time a sale in a lower-income year. This calculator turns the 2026 gain rules into a concrete estimate so you can make informed sell decisions.
Capital Gain = Sale Proceeds - Cost Basis. Short-term federal tax = Gain x ordinary rate. Long-term federal tax = Gain allocated across 0%, 15%, and 20% tiers using 2026 taxable-income thresholds. NIIT = lesser of net investment income or MAGI above the statutory threshold, multiplied by 3.8%. State Tax = Gain x State Rate. Total Tax = Federal + NIIT + State. Net Proceeds = Sale Proceeds - Total Tax.
Result: Tax: $1,904 / Net Proceeds: $16,096
You bought stock for $10,000 and sold for $18,000, realizing an $8,000 long-term gain. With $210,000 of taxable income before the sale, the gain falls into the 15% long-term tier for a $1,200 federal tax. Adding 3.8% NIIT ($304) and 5% state tax ($400) brings total tax to $1,904. Your net after-tax proceeds are $16,096, an after-tax return of 60.96% on the original $10,000.
For 2026, single filers pay 0% on long-term gains up to $49,450 of taxable income, 15% up to $545,500, and 20% above that. Married-filing-separately thresholds are $49,450 and $306,850. Married-filing-jointly / qualifying surviving spouse thresholds are $98,900 and $613,700. Head of household thresholds are $66,200 and $579,600. Short-term gains are folded into ordinary income and taxed at your marginal rate, which can still reach 37%.
Tax-loss harvesting involves selling losing investments to realize capital losses that offset gains. Excess losses up to $3,000 per year can offset ordinary income, with any remaining carried forward indefinitely. This strategy can materially improve after-tax results for taxable portfolios.
The one-year dividing line between short-term and long-term gains is strict. Selling one day early can cost thousands in extra taxes. If you are near the one-year mark, consider waiting. Similarly, if you expect a lower income next year (retirement, sabbatical, career change), deferring the sale to January may place you in a lower bracket, reducing both federal and state tax bills.
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This calculator estimates tax on a single realized capital gain by subtracting cost basis from sale proceeds, then applying the selected federal capital-gains rate, optional Net Investment Income Tax, and an optional state tax rate. It is designed as a planning calculator for one gain event rather than a full tax return.
The output does not determine eligibility for the 0%, 15%, or 20% long-term capital-gains bands on its own, and it does not compute the NIIT base from full MAGI. Use it to estimate the tax impact once you already know the applicable rate assumptions for the transaction you are modeling.
Short-term gains are profits on assets held one year or less and are taxed at your ordinary income rate (10-37%). Long-term gains apply to assets held over one year and are taxed at 0%, 15%, or 20% depending on your taxable income. The preferential long-term rates can save you thousands on the same gain amount.
The NIIT is a 3.8% surtax on net investment income for individuals with MAGI above $200,000 (single or head of household), $125,000 (married filing separately), or $250,000 (married filing jointly / qualifying surviving spouse). It applies to interest, dividends, capital gains, rental income, and royalties. It is in addition to the regular capital gains tax, effectively raising the top long-term rate to 23.8%.
Hold assets over one year for lower rates, harvest losses to offset gains, donate appreciated assets to charity for a double benefit (no gain + deduction), use tax-advantaged accounts (IRA, 401k) where gains grow tax-deferred, and consider Qualified Opportunity Zone investments for gain deferral and exclusion. Combining several of these strategies in a single tax year can significantly reduce your overall capital gains liability.
Most states tax capital gains as ordinary income. Seven states - Alaska, Florida, Nevada, South Dakota, Texas, Washington, and Wyoming - have no income tax. A few states offer preferential rates for long-term gains or exclude a portion. Always check current state rules, as they change frequently.
This calculator estimates tax on a realized gain and does not track wash sale adjustments. If you repurchase a substantially identical security within 30 days before or after a loss sale, the loss is disallowed and added to the replacement security cost basis. Use the Cost Basis Calculator for wash-sale-aware tracking.
Yes. Inherited assets receive a stepped-up cost basis to the fair market value at the date of death. This eliminates capital gains tax on all appreciation during the decedent's lifetime. Any gain realized after inheritance is measured from the stepped-up basis, which can dramatically reduce the tax owed.