Capital Gains Tax Calculator

An asset held more than one year before sale produces a long-term capital gain, taxed at the preferential 0%, 15%, or 20% federal rate. An asset held one year or less produces a short-term capital gain, taxed as ordinary income at your marginal federal rate (10% up to 37%). The same dollar gain can be taxed very differently depending on holding period.

The 0/15/20% LTCG rates are bracketed by total taxable income (ordinary income plus the long-term gain). For 2025: single filers pay 0% on LTCG up to $48,350 of total taxable income, 15% up to $533,400, and 20% above. Brackets are higher for married filing jointly and head of household. The calculator stacks the gain on top of your other taxable income.

Cost basis is what you paid for the asset, adjusted for any commissions, reinvested dividends, or other basis adjustments. For most stocks, basis is purchase price plus brokerage commission. For real estate, basis includes the purchase price plus capital improvements and certain closing costs. Your broker or the IRS Form 8949 reporting documents are the official source.

The NIIT is an additional 3.8% federal tax on investment income (including capital gains) for higher-income taxpayers. It applies when modified AGI exceeds $200,000 (single) or $250,000 (married jointly). This calculator does not model NIIT to keep the math simple; high-income filers should add it manually if it applies.

Most states tax capital gains the same as ordinary income at their state income tax rates. A few states (Washington, with the new 7% LTCG tax, and certain bracket arrangements in others) treat them specially, and several states (Texas, Florida, Nevada, et cetera) do not tax personal income at all. Enter your state's effective capital-gains tax rate as a percent; the calculator applies it to the gain.

Yes, but with limits. Capital losses first offset capital gains of the same type, then offset gains of the other type, then up to $3,000 per year offsets ordinary income (single or married jointly). Excess losses carry forward to future years. This calculator does not model loss carryovers; enter the net gain or a 0 sale value if the position is at a loss.

No. This is a planning estimate. Real capital-gains tax depends on basis adjustments, wash-sale rules, holding-period nuances, AMT, NIIT, state-specific treatment, and carryover losses. Consult a tax professional before making decisions based on the output.