Capital Gains Calculator
Selling a stock, fund or home is taxable — but only on the profit. This free US capital gains calculator estimates your gain and the tax owed at short-term or long-term rates, so you can plan a sale with the real after-tax number in mind.
What is a capital gains calculator?
A capital gains calculator estimates the profit you make when you sell an asset and the tax the IRS would charge. In the US, gains are split by how long you held the asset. A short-term gain is held one year or less and taxed at your ordinary income bracket; a long-term gain is held more than a year and taxed at the lower preferential rates of 0%, 15% or 20% depending on your income.
To use it you enter your cost basis — roughly what you paid, plus qualifying improvements and fees — and your sale price. The difference is the gain. The tool then applies the rate you select for the holding period to estimate the tax and your after-tax proceeds. Because tax is only on the gain and not the sale price, this is the fastest way to see what a sale nets you after the IRS takes its share.
How to use
- Enter your cost basis (what you paid, including fees or improvements).
- Enter the sale price you received.
- Choose the holding period — short-term or long-term.
- Set your relevant tax rate, then click Calculate Capital Gains.
How capital gains tax is calculated
Gain = sale price − cost basis
Estimated tax = gain × applicable rate
After-tax proceeds = sale price − estimated tax
Short-term gains use your ordinary income rate; long-term gains use the 0/15/20 percent capital gains schedule.
Example
With the defaults — a $20,000 cost basis, a $45,000 sale price, a long-term holding period and a 15% long-term rate — click Calculate Capital Gains. The gain is $25,000, the estimated tax is $3,750, and your after-tax proceeds are $41,250. Now switch the holding period to short-term at a 24% rate and the tax jumps to $6,000, leaving just $39,000 — a clear reminder of the advantage of holding investments longer than a year.
Common use cases
- Plan a stock or fund sale: know the tax before you sell so you can compare strategies.
- Compare holding periods: see the tax savings from long-term sales.
- Offset with losses: pair gains with tax-loss harvesting to reduce your bill.
- Estimate a home sale: gauge the taxable gain if you don't qualify for the primary-home exclusion.
Pro tips
- Hold past one year: long-term gains are taxed at much lower preferential rates than ordinary income.
- Use losses: capital losses offset gains first, then up to $3,000 of ordinary income each year.
- Time the sale: selling in a lower-income year can push you into a lower long-term bracket.
- Remember the extra tax: high earners may also owe the 3.8% net investment income tax, which this tool does not include.
FAQ
What is a capital gain?
The profit you make when you sell an asset for more than you paid — the sale price minus your cost basis.
What is the difference between short-term and long-term?
A holding period of one year or less is short-term, taxed at ordinary income rates. More than one year is long-term, taxed at lower rates.
How do I find my cost basis?
Generally what you paid, plus certain improvements and fees, less any depreciation or earlier returns. Use the figure on your tax statement.
What are the long-term capital gains rates?
For most taxpayers the rates are 0%, 15% or 20%, depending on your taxable income and filing status.
How is the gain calculated?
Gain = sale price − cost basis. Bought at $20,000 and sold for $45,000, the gain is $25,000.
Do I pay tax on the whole sale price?
No. You are taxed only on the gain, not the sale price. The original cost of the asset is not taxed in the sale.
How do I avoid capital gains tax?
Lower it by holding assets longer than a year, harvesting losses, using a retirement account, or timing sales to a lower-income year.
What is capital loss harvesting?
Selling losing investments to offset gains. Losses offset gains first, then up to $3,000 of ordinary income each year.
Does this calculator handle the net investment income tax?
No. It estimates federal tax at your chosen bracket, but does not include state tax or the extra 3.8% net investment income tax.
Is this capital gains calculator free?
Yes. It runs entirely in your browser and no data is uploaded anywhere.
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