Capital Gains Tax Calculator 2026: 0%, 15%, 20% and NIIT

Updated October 4, 2026. Quick answer: Long-term gains sit on top of your other taxable income, and only the part that lands above the 0% limit is taxed, at 15% until the 15% limit and 20% above it; short-term gains are taxed as ordinary income, and a 3.8% net investment income tax can apply on top for higher incomes. Calculated for a single filer with $30,000 of other taxable income who sells for a $40,000 long-term gain, $19,450 is taxed at 0% (the 2026 zero rate limit for single filers is $49,450) and $20,550 (computed) at 15%, so the federal tax is $3,082.50 (computed from Revenue Procedure 2025-32), against $6,760 (computed) if the same gain had been ordinary income. Enter your own numbers below.

Related reading on this site: IRS Publication 544.

Read box by box from the IRS form text: Form 2439 boxes 1a to 1d.

IRS worksheets from the 2025 Form 1040 instructions, read line by line: Schedule D Tax Worksheet.

Schedule D and Schedule E (Form 1040) for 2025, read line by line: Schedule D line 8a, Schedule D lines 13 to 15 and Schedule D lines 16 and 17.

Form 8949 for 2025, read code by code: Form 8949 code M, Form 8949 code N and Form 8949 code S.

Form 1040 for 2025, lines 12 to 38 read line by line: Form 1040 line 16.

Form 1040 for 2025, read line by line: Form 1040 lines 3a and 3b and Form 1040 line 7.

Calculate the tax on your capital gains

This page prices a sale you have already made or are weighing. It does not tell you whether to sell, hold or give the asset away. The result runs on this page and sends nothing anywhere. Your other taxable income is the figure on your 2026 return after the standard or itemized deduction and before these gains. The 2026 standard deductions are in the IRS release: “For tax year 2026, the standard deduction increases to $32,200 for married couples filing jointly. For single taxpayers and married individuals filing separately, the standard deduction rises to $16,100 for tax year 2026, and for heads of households, the standard deduction will be $24,150.”

Enter the net gain for each holding period, after netting that period’s losses against its gains. Qualified dividends are taxed at the same 0%, 15% and 20% rates, so you can add them to the long-term box for the federal income tax. The ordinary brackets are the 2026 tables in Revenue Procedure 2025-32. State tax is a rate you enter, applied to the whole gain, because states differ.

2026 capital gains tax rates and thresholds

The thresholds that set the 0%, 15% and 20% rates come from the maximum capital gains rate section of the Revenue Procedure: “For taxable years beginning in 2026, the maximum zero rate amounts and maximum 15 percent rate amounts under § 1(j)(5)(B), as adjusted for inflation, are as follows:” They are measured against total taxable income, gain included, not against the gain alone. The 3.8% tax uses modified adjusted gross income instead, with thresholds that are not indexed for inflation.

How a long-term gain is stacked on your income

The calculation works in layers. Your ordinary income, including any short-term gain, fills the bottom of the taxable income scale. The long-term gain is stacked on top. The IRS worksheet that does this is the Qualified Dividends and Capital Gain Tax Worksheet in the Form 1040 instructions. Its steps include “Subtract line 8 from line 7. This amount is taxed at 0%”, “Multiply line 17 by 15% (0.15)” and “Multiply line 20 by 20% (0.20)”, and it ends with “Tax on all taxable income. Enter the smaller of line 23 or line 24.” That last step matters in a narrow range: when your other income sits just under the top of the 12% bracket, ordinary rates on the gain can cost less than 15%, and the smaller figure is the tax. The calculator applies it and says so when it does.

1. Take your other taxable income and add the short-term gain. That total is taxed at ordinary rates, and the short-term gain is taxed in the brackets it fills.
2. Place the long-term gain above it. The part below the 0% limit is taxed at 0%.
3. The part from there up to the 15% limit is taxed at 15%, and anything above is taxed at 20%.
4. Compare with ordinary rates on the whole amount and keep the smaller tax.

Worked example, single filer, $30,000 of other taxable income, $40,000 long-term gain. The 0% limit is $49,450, so the first $19,450 of the gain ($49,450 minus $30,000) is taxed at 0%. The remaining $20,550 (computed) is taxed at 15%: $20,550 x 15% = $3,082.50 (computed). Federal tax is $3,082.50. At ordinary rates the same gain would cost $6,760 (computed).

Second example with both kinds of gain, single filer, $45,000 of other taxable income, $5,000 short-term gain and $30,000 long-term gain. The short-term gain lifts ordinary income to $50,000, all in the 12% bracket: $5,000 x 12% = $600 (computed). That is already above the $49,450 zero rate limit, so the whole $30,000 long-term gain is taxed at 15%: $30,000 x 15% = $4,500 (computed). Federal tax is $5,100 (computed).

What a $40,000 long-term gain costs at different incomes

Single filer, no short-term gain, no other investment income. The same gain is taxed at 0% in the low part of the scale, at 15% in the middle and at 20% only at the top.

Short-term versus long-term: the holding period

The split depends on how long you held the asset. The IRS puts it this way: “Generally, if you hold the asset for more than one year before you dispose of it, your capital gain or loss is long-term. If you hold it one year or less, your capital gain or loss is short-term.” The Code defines a long-term gain as “gain from the sale or exchange of a capital asset held for more than 1 year”. The tax difference is large: “Net short-term capital gains are subject to taxation as ordinary income at graduated tax rates.” The 2026 ordinary rates are on the short-term capital gains rate page.

A $20,000 gain, single filer, by other taxable income, taxed as short-term and as long-term:

Exceptions to the one-year rule exist for property acquired by gift or from a decedent and for some other assets; the IRS topic sends you to Publication 544 for them. The gains are reported on Form 8949 and Schedule D.

The 3.8% net investment income tax

Higher incomes can owe an additional tax on investment gains. Section 1411 provides: “there is hereby imposed (in addition to any other tax imposed by this subtitle) for each taxable year a tax equal to 3.8 percent of the lesser of” net investment income or the amount by which modified adjusted gross income exceeds the threshold. The thresholds are set in the statute: “in the case of a taxpayer making a joint return under section 6013 or a surviving spouse (as defined in section 2(a)), $250,000”, half of that for married filing separately, and “in any other case, $200,000”. Net investment income includes “net gains from the disposition of property such as stocks, bonds, mutual funds, and real estate (to the extent taken into account in computing taxable income)”. It does not include wages: “The NIIT doesn’t apply to wages, unemployment compensation, or income from an active business.”

Worked example, single filer with $180,000 of adjusted gross income before a $50,000 long-term gain. Modified AGI with the gain is $230,000 (computed), which is $30,000 over the $200,000 threshold. The tax applies to the smaller of that excess and the $50,000 of net investment income, so $30,000 x 3.8% = $1,140 (computed). The calculator shows only the tax your gains add: the 3.8% tax with the gains, minus the 3.8% tax on your other investment income alone. More detail is on the 2026 net investment income tax page and Form 8960.

A $50,000 long-term gain, single filer, by adjusted gross income before the gain:

Three choices the tax number does not make

1. Whether to sell. The tax is one cost of selling. Whether to sell, hold, give the asset away or leave it to heirs depends on the investment, your other holdings and your plans, and this page prices none of that.

2. Which year and which lots. The tax above depends on the other income in the same year, and a gain pushed into a lower-income year can fall in the 0% range. Which shares you sell changes the gain too. Offsetting gains with losses is on the tax loss harvesting page, and the room left in the 0% range is on the capital gains harvest window page.

3. How the proceeds are used. Spreading a large sale over several years, giving appreciated shares to charity, or reinvesting changes the outcome. Selling a home has its own exclusion, covered by the home sale exclusion calculator.

Where this calculator stops

It prices net gains as short-term or long-term at the federal level. It does not handle collectibles and section 1202 stock (taxed at up to 28%), unrecaptured section 1250 gain (up to 25%), or gains on assets held in a retirement account. It does not net losses for you: “If your capital losses exceed your capital gains, the amount of the excess loss that you can claim to lower your income is the lesser of $3,000 ($1,500 if married filing separately) or your total net loss”, so enter each holding period’s net gain, not its losses. It also does not handle the home sale exclusion, the alternative minimum tax, credit and deduction phase-outs, the 3.8% tax on trusts, or investment expenses that reduce net investment income. State tax is the rate you enter times the gain. The result is an estimate, and your return decides the actual amount.

Common mistakes

• Entering your salary as other taxable income. Use taxable income after the standard or itemized deduction.
• Measuring the 0% limit against the gain alone. The limit applies to total taxable income, so the gain only gets 0% where your other income leaves room under it.
• Treating short-term gains like long-term gains. A gain on an asset held a year or less is taxed at your ordinary rate.
• Forgetting the 3.8% tax. It runs off modified AGI and does not appear in the 15% or 20% rate.
• Entering a loss as a gain of zero and ignoring it. A net loss is limited to $3,000 against other income, with the rest carried forward.
• Assuming a rate cannot be below 15% at the top of the 12% bracket. The smaller-of rule can make the tax lower than 15% of the gain in that range.

Related: short-term capital gains rates, the net investment income tax, long-term capital gains brackets, tax loss harvesting, and Schedule D.

Sources

• 26 U.S.C. section 1222, Other terms relating to capital gains and losses: https://www.govinfo.gov/link/uscode/26/1222 (section page)
• 26 U.S.C. section 1411, Imposition of tax (net investment income): https://www.govinfo.gov/link/uscode/26/1411 (section page)
• IRS Topic no. 409, Capital gains and losses: https://www.irs.gov/taxtopics/tc409
• IRS Topic no. 559, Net investment income tax: https://www.irs.gov/taxtopics/tc559
• IRS 2025 Instructions for Form 1040, Qualified Dividends and Capital Gain Tax Worksheet: https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
• IRS Instructions for Form 8960, Net Investment Income Tax: https://www.irs.gov/pub/irs-pdf/i8960.pdf
• IRS news release IR-2025-103, tax year 2026 inflation adjustments: https://www.irs.gov/newsroom/irs-releases-tax-inflation-adjustments-for-tax-year-2026-including-amendments-from-the-one-big-beautiful-bill
• IRS Revenue Procedure 2025-32 (2026 inflation adjustments): https://www.irs.gov/pub/irs-drop/rp-25-32.pdf

Read from the Internal Revenue Code sections, the IRS pages and Revenue Procedure linked above on October 4, 2026. General information, not legal or tax advice. Your own facts decide the outcome, and your plan administrator, a tax professional or a benefits advisor is the right place to confirm anything consequential.