Capital Gains Tax Calculator 2026 — Short & Long-Term Rates

Federal tax on an investment gain depends heavily on how long you owned the asset before selling it in 2026. Long-term gains keep their preferential treatment at 0%, 15%, and 20%, with the rate set by where your income falls. Short-term gains get no such break; they fold into your ordinary income and can be taxed at rates reaching 37%.

Sorting the gain comes first. Anything held a year or less counts as short-term, anything held longer as long-term, and the appropriate rate is then applied against your total taxable income and filing status. High earners also face the 3.8% Net Investment Income Tax, charged on the gain or on the part of income above $200,000 ($250,000 for joint filers, $125,000 married filing separately), whichever is smaller. The 0%, 15% and 20% thresholds are the inflation-adjusted figures for 2026; the NIIT thresholds are fixed in the law and are not indexed for inflation.

One detail trips up a lot of sellers: the holding period is measured to the day. Unloading an asset even 24 hours before the one-year mark flips it from long-term to ordinary rates and can swing the bill sharply. The optional state field adds only a rough figure: it applies one rate per state to the whole gain, so check your state's own brackets and rules before relying on it.