Capital Gains Tax Calculator
Enter your cost basis, sale proceeds, and estimated tax rates to see gain/loss, tax owed, and after-tax proceeds.
Show calculation breakdown
- Gain = proceeds − cost basis − fees
- Combined tax rate = federal + state/local
- Tax owed = max(gain, 0) × combined rate
- After-tax proceeds = proceeds − fees − tax (or + benefit if you choose to estimate loss offset)
Note: Real-world capital gains rules can include brackets, net investment income tax (NIIT), wash sales, carryovers, and specific country/state rules. This calculator is meant for quick planning and comparisons.
What this capital gains tax calculator tells you
If you’re selling a stock, crypto, property, or any investment, the question is usually simple: how much will I keep after taxes? This calculator estimates your capital gain (or loss), applies an estimated tax rate, and shows your after-tax proceeds. Run 2-3 scenarios: conservative, baseline, and optimistic.
Key inputs: cost basis, proceeds, and fees
Most people get tripped up on the starting point: cost basis. In plain English, cost basis is what you paid for the investment, including certain purchase costs. Proceeds are what you received when you sold. The difference between proceeds and basis (minus any transaction fees) is your gain or loss.
Fees matter more than they look. Brokerage commissions may be small today, but spreads, exchange fees, and closing costs (especially on property) can be meaningful. If you’re comparing two selling options, enter the fees for each option to see how the final number changes.
Short-term vs long-term: why the holding period matters
Many tax systems treat gains differently depending on how long you held the asset. In the US, gains are typically called short-term if you held the asset under a year and long-term if you held it a year or longer. Long-term rates are often lower, which can make the difference between “sell now” and “wait a little longer.”
This page asks you to select a holding period mainly as a reminder: the right rate depends on your situation. If you’re not sure what rate to use, try a few values (for example 15% vs 24%) and see how sensitive your after-tax proceeds are.
How to estimate your tax rate (without overthinking it)
For quick planning, you can treat your capital gains tax as a simple percentage and apply it to the gain. In reality, your rate can depend on brackets, filing status, income level, and add-ons. But if your goal is to decide between a few options, sell today vs later, sell all vs part, or rebalance a portfolio, an estimate is usually enough.
Start with a baseline rate you believe is plausible (like 15% federal and 5% state), then adjust until the result “feels right.” If you want to understand the impact of a percentage change, you can sanity-check the math using our Percent Calculator.
Using the results: plan the cash you’ll actually have
The after-tax proceeds number is the practical output. It helps you answer questions like:
- How much cash will I have available for my next investment?
- Can I fund a goal without dipping into an emergency buffer?
- Is it worth harvesting a loss to reduce this year’s taxes?
If you’re thinking in broader terms, like how this sale changes your overall picture, pair this tool with the Net Worth Calculator. And if your sale is meant to fund a future plan, you can project what the after-tax proceeds might grow into with the Compound Interest Calculator.
Common mistakes (and how to avoid them)
The most common mistake is mixing up account values. People sometimes enter the market value at purchase instead of the true basis, or forget that they reinvested dividends. Another common issue is treating a loss like “negative tax owed.” A loss can be valuable, but the benefit depends on your broader tax picture and any carryover rules.
Finally, don’t forget inflation. If you’re comparing a gain from years ago to today’s dollars, the purchasing power may be very different. Use our Inflation-Adjusted Value Calculator if you want to put an older purchase price into today’s terms.
More tools and next steps
When you’re done here, browse the full library at /calculators/. A good workflow is to estimate the tax hit, confirm the percent math, then test what you’ll do with the proceeds. That’s usually enough to make a confident decision without building a spreadsheet.
FAQ
What is a capital gain?
A capital gain is the profit you make when you sell an asset for more than its cost basis. In this calculator, gain = proceeds − basis − fees.
What is cost basis, exactly?
Cost basis is usually what you paid for the asset, plus certain purchase costs. For investments with multiple buys, your broker or records determine the basis method used.
Do transaction fees reduce my taxable gain?
Often, yes: fees connected to buying or selling can affect your net gain. This tool subtracts fees before applying the tax rate to keep the estimate practical.
What’s the difference between short-term and long-term gains?
Short-term gains are typically taxed like ordinary income, while long-term gains may qualify for lower rates. The exact cutoff and rates depend on your jurisdiction.
Does this include brackets or NIIT (Net Investment Income Tax)?
No. This is a flat-rate estimator. If you need bracket-level accuracy or NIIT, use this as a baseline and confirm with a tax professional or tax software.
