Capital Gains Tax Calculator
Estimate federal capital gains tax based on whether the gain is short-term (ordinary income) or long-term (preferential rate).
Inputs
Capital gains tax owed
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Tax rate applied
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Net investment income tax (3.8%)
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After-tax gain
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Effective rate on gain
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About Capital Gains Tax Calculator
Long-term vs short-term
Long-term (held > 1 year) is taxed at 0%, 15%, or 20% based on income — much lower than ordinary rates (up to 37%). Always check the holding period before selling.
NIIT
The 3.8% Net Investment Income Tax applies to investment income (incl. capital gains) when MAGI exceeds $200k single / $250k MFJ. Adds 3.8% on top of regular cap gains rate.
Loss harvesting
You can offset gains with capital losses dollar-for-dollar. Excess losses up to $3,000/year can offset ordinary income; the rest carries forward indefinitely.