What is the Net Investment Income Tax (NIIT)?

An additional 3.8% federal tax on investment income (including capital gains) for single filers with modified adjusted gross income above $200,000 ($250,000 married filing jointly). It's not included in this calculator's estimate — if your total income is near or above that threshold, budget for it separately.

Does this include state capital gains tax?

No — this is federal only. Many states tax capital gains as ordinary income at their own rates, and a few have no state income tax at all, so your total liability depends heavily on where you live.

Why does 'other income' matter for a capital gain?

Long-term capital gains rates are determined by your total taxable income, not the gain in isolation — the IRS stacks your ordinary income first, then layers the capital gain on top to see which bracket(s) it falls into.

Does this use my detected region's tax data if I'm outside the US?

Yes, for US, UK, Canada, Australia, and India (listed equity) — each uses that region's own real capital-gains mechanism, not a US number with the currency symbol swapped. See the next question for how each one actually works. Any other region falls back to the US estimate with a clearly labeled disclaimer, not a silent guess.

How does each supported region actually calculate the tax?

US: 0/15/20% long-term brackets (short-term uses ordinary income brackets), stacked on your other income. UK: a flat 18%/24% rate regardless of holding period, after a £3,000 Annual Exempt Amount. Canada: 50% of the gain is added to ordinary income and taxed at your marginal rate — no holding-period distinction. Australia: assets held over 12 months get a 50% CGT discount before being added to assessable income; 12 months or less, the full gain counts. India: modeled for listed equity only — a flat 12.5% above a ₹1.25 lakh exemption if held over 12 months, or a flat 20% if not, independent of your other income.

Is the 3.8% NIIT added to the tax figure shown?

No — when your total income (other income plus the gain) crosses $200,000, the calculator shows a note that you may owe it, but doesn't add it into the displayed estimate. Add roughly 3.8% of the gain yourself if that note appears.

Does this use married-filing-jointly brackets?

No — single-filer thresholds only. Married-filing-jointly bracket boundaries are roughly double at each level, so a joint filer's actual tax will typically be lower than what this calculator estimates.

What exactly counts toward cost basis?

Your original purchase price plus amounts that increase it — reinvested dividends, and for real estate, capital improvements (not routine repairs or maintenance). Keeping records of these reduces your taxable gain when you eventually sell.

Can this calculate a loss instead of a gain?

No — the tool only computes tax on a gain, floored at $0 if your sale price is below your cost basis. A capital loss isn't modeled here; losses can offset other gains through tax-loss harvesting, a separate calculation.

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Finance

Capital Gains Tax Calculator

Estimate federal tax on a short- or long-term investment gain.

🔒 Runs entirely in your browser — nothing here is ever uploaded

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Last reviewed 2026-08-29

About the Capital Gains Tax Calculator

Estimates tax owed on an investment gain using your detected or selected region's real capital gains rules — US, UK, Canada, Australia, and India (listed equity) are each modeled with their own actual mechanism, not just a currency-converted US estimate.

100% Free Runs in Your Browser No Sign-Up Required

How to use it

Enter the Sale price and Cost basis (what you originally paid, plus any improvements).
Enter your Other taxable income for the year, if shown — this determines which bracket the gain stacks into (not used for every region's model).
Choose whether you held the asset Long-term or Short-term, if shown — some regions' rules don't distinguish holding period at all.
Read the estimated tax, effective rate, and net proceeds in the result panel.

Formula

Each region uses its own real mechanism, not one formula stretched across all of them:

US — long-term gains use the 2026 single-filer capital-gains brackets (0%/15%/20%), short-term gains use the ordinary income brackets; both stack on top of other income.

UK — Capital Gains Tax applies the same 18%/24% rates regardless of holding period, after subtracting the £3,000 Annual Exempt Amount from the gain.

Canada — no separate CGT: 50% of the gain (the "inclusion rate") is added to ordinary income and taxed at your federal marginal rate, regardless of holding period.

Australia — no separate CGT: assets held over 12 months get a 50% CGT discount (only half the gain counts as assessable income); held 12 months or less, the full gain counts. Either way it's then taxed at your marginal rate.

India — modeled for listed equity/equity mutual funds specifically: long-term (over 12 months) gains above a ₹1.25 lakh exemption are taxed at a flat 12.5%; short-term gains at a flat 20%, with no exemption and no stacking on other income.

Worked example

US example: a $20,000 long-term gain on top of $85,000 of other income falls entirely in the 15% bracket for a single filer in 2026, since $85,000 is already above the $49,450 threshold and $105,000 total stays under $545,500 — so the estimated tax is $3,000. India example (listed equity): a ₹200,000 long-term gain, after the ₹125,000 exemption, leaves ₹75,000 taxable at the flat 12.5% LTCG rate — ₹9,375 in tax, regardless of other income.

2026 long-term capital gains rates (US, single filer)

2026 long-term capital gains rates (US, single filer)
Total taxable income (incl. gain)	Rate
$0 – $49,450	0%
$49,450 – $545,500	15%
Over $545,500	20%
Plus: Net Investment Income Tax (NIIT)	+3.8% on investment income if MAGI is over $200,000 — not included in this calculator's estimate

Interpreting your result

Figures are federal/national-level only — state, provincial, or sub-national capital gains taxes aren't included anywhere. US: single-filer only; high earners may also owe the 3.8% Net Investment Income Tax on top of this estimate, see the FAQ. India: modeled for listed equity only — property, gold, and unlisted shares use different rates and a 24-month holding threshold, not covered here. A visitor whose region isn't sourced yet sees a general/US estimate with a visible disclaimer, not a silent guess.

Recommendations

• Holding an asset past the one-year mark before selling, if you can, moves the gain from ordinary rates (up to 37%) to the much lower long-term rates — often the single biggest lever you control.
• Cost basis includes more than the purchase price — reinvested dividends and capital improvements (for property) increase your basis and reduce your taxable gain, so keep records.
• A capital loss on another investment sold the same year can offset a gain (tax-loss harvesting) — not modeled here, but worth exploring with a tax professional if you're carrying losses.

Frequently asked questions

Long-term means you held the asset for more than one year before selling; short-term means one year or less. The distinction matters a lot — long-term gains get the preferential 0/15/20% rates, while short-term gains are taxed at your full ordinary income rate, which can be more than double.