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0% capital gains calculator

Free, no signup. A federal capital gains tax calculator for retirees: how much long-term gain you can realize in 2026 at the 0% rate given your other income and Social Security, and what the next $1,000 of gain costs. Built for tax-gain harvesting in low-income years.

Updated · By Berkay Kolay

The calculator

Gains you can take at 0%$90,750With no added federal income tax
Top of the 0% rate$98,900Taxable income; yours before gains is $2,150
Tax on the next $1,000$150Federal, past the 0% room

You can realize about $90,750 of long-term gains this year without adding federal income tax.

2026 long-term capital gains rates

Taxable income limits for long-term gains and qualified dividends, 2026
Filing status0% up to15% up to20% above
Single$49,450$545,500$545,500
Married filing jointly$98,900$613,700$613,700
Head of household$66,200$579,600$579,600

How gains stack on top of your income

Long-term gains and qualified dividends sit on top of your ordinary taxable income. The part that fits under the 0% line is taxed at 0%, and the rest at 15%. A married couple with $40,000 of ordinary taxable income after deductions has $98,900 − $40,000 = $58,900 of room. Gains also raise your adjusted gross income, so deductions that phase out with income, like the senior deduction, can shrink as you add them; the calculator accounts for that.

Tax-gain harvesting

In a year with room at 0%, you can sell investments that have gained, pay no federal tax, and buy them straight back. Your cost basis resets higher, so the gain you just realized is never taxed later. The wash-sale rule only applies to losses, so buying back right away is allowed. Early retirees before Social Security and RMDs, and anyone with a low-income year, have the most room.

The Social Security catch

Gains count in the combined income that decides how much of your Social Security is taxable. Inside that range, each dollar of gain can make 50 or 85 cents of benefits taxable at your ordinary rate, so a gain taxed at 0% can still raise your tax bill. The calculator stops the room at the point where federal tax would start to rise, which can be well before the 0% line.

State tax and Medicare premiums

Most states tax capital gains as ordinary income, so “0%” is federal only. Gains also raise the modified AGI that sets Medicare IRMAA two years later; the IRMAA calculator shows the thresholds. The 3.8% net investment income tax starts at $200,000 single and $250,000 joint, above most 0% budgets.

Assumptions and sources

One 2026 return under current law, with the standard deduction, no alternative minimum tax and no local tax. The same tax engine runs inside Killion’s planner when you turn tax on in a paid plan. Estimates for planning, not tax advice. Short-term gains are taxed as ordinary income and are not covered.

Figures checked on against IRS Rev. Proc. 2025-32, 2026 inflation adjustments (PDF), IRS Publication 915, Social Security and equivalent railroad retirement benefits and IRS, questions and answers on the net investment income tax.

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Frequently asked questions

What are the 2026 capital gains tax brackets?
Long-term gains are taxed at 0% up to $49,450 of taxable income single, $98,900 married filing jointly and $66,200 head of household; at 15% up to $545,500, $613,700 and $579,600; and at 20% above that.
How does the 0% capital gains rate work?
Gains stack on top of your ordinary taxable income. The part that fits under the 0% line is taxed at 0% and the rest at 15%. A couple with $40,000 of ordinary taxable income can take $58,900 of gains at 0%.
What is tax-gain harvesting?
Selling investments with a gain in a year when the gain is taxed at 0%, then buying them back. Your cost basis resets higher, so that gain is never taxed later. The wash-sale rule applies only to losses.
Does Social Security affect the 0% capital gains rate?
Yes. Gains count in the income that decides how much of your benefits are taxable, so a gain taxed at 0% can make more Social Security taxable at your ordinary rate. The calculator stops where your tax would start to rise.
Do states tax capital gains?
Most states with an income tax tax capital gains as ordinary income, so the 0% rate is federal only. The calculator shows the state tax on your 0% room when you pick a state.
Do capital gains raise Medicare premiums?
They can. Gains count in the modified AGI that Medicare uses two years later to set IRMAA, so a large harvest at 65 or older, or in the two years before, can raise Part B and Part D premiums.
Can I use this as a capital gains tax calculator for a property sale?
For the federal rate on a long-term gain, yes: enter the gain and the calculator shows how much of it fits in the 0% rate and what the next $1,000 costs. If the property was your main home for two of the last five years, the first $250,000 of gain ($500,000 for a married couple) is excluded first. Depreciation taken on a rental is taxed at up to 25%, which the calculator does not model.
Does it work for stock and fund sales?
Yes. Gains on stocks, funds and ETFs held more than a year are long-term and use the 0%, 15% and 20% rates shown here. Gains on investments held a year or less are short-term and taxed as ordinary income.
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