Capital Gains Tax Calculator
Free capital gains tax calculator for stocks. Estimate short-term and long-term tax on profits using cost basis, sale proceeds, and federal brackets. Educational estimate only.
Estimate short-term vs long-term capital gains tax on a stock sale using purchase price, sale price, holding period, and your tax bracket. Plan exits with tax drag in mind — not after the fact.
What is a capital gains tax calculator?
A capital gains tax calculator estimates the tax hit when you sell stocks (or similar assets) for more than you paid. People search for it before year-end selling, before taking a large profit, or when comparing “sell now” vs “wait for long-term rates.” This tool gives a clear educational estimate of federal + optional state tax and your after-tax profit.
Short-term vs long-term capital gains
Short-term (typically held ≤ 1 year): taxed like ordinary income in the US — your marginal bracket matters. Long-term(typically held > 1 year): usually taxed at preferential 0% / 15% / 20% federal rates depending on taxable income and filing status.
Waiting a few weeks for long-term status can be worth thousands on a large gain — which is why holding-period math belongs next to price targets.
Capital gain formula
Gain = Sale proceeds − Cost basis
Cost basis is generally what you paid including commissions (adjusted for splits, reinvested dividends in some accounts, etc.). Sale proceeds are what you receive after sell-side fees. Tax ≈ gain × applicable rate(s) when the gain is positive. Example: $10,000 basis → $15,000 sale = $5,000 gain; at 15% LTCG ≈ $750 federal estimate before state/NIIT.
How to use this free capital gains calculator
- Enter cost basis and sale proceeds in USD.
- Choose short-term or long-term holding period.
- Short-term: enter other taxable income so the gain stacks into illustrative brackets. Long-term: pick 0%, 15%, or 20%.
- Add a flat state % if your state taxes capital gains.
- Compare after-tax profit to your pre-tax P&L from the stock profit calculator.
Planning tips (not advice)
- Harvest losses carefully: Tax-loss harvesting can offset gains, but wash-sale rules exist.
- Don't let the tax tail wag the dog: Holding a broken thesis just for a lower rate can cost more than the tax saved.
- Know your lot method: FIFO vs specific identification changes which lots — and which gains — you realize. Reconstruct lots with the average cost calculator.
More detail: capital gains tax on stocks guide.
Frequently asked questions
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Not tax, legal, or investment advice. Brackets and rules change. Confirm with IRS publications, your brokerage 1099-B, and a qualified tax professional before filing or trading on tax assumptions.
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