Capital Gains Tax Calculator
Enter your purchase and sale prices, holding period, and income to calculate your 2025 capital gains tax using federal rates.
Asset
Your Tax Situation
Capital Gain
$8,000.00
Long-term capital gains rate
Long-Term Rate Breakdown
0%
$0.00 taxed here
15%
$8,000.00 taxed here
20%
$0.00 taxed here
2025 federal rates. State capital gains taxes not included.
How to Use the Capital Gains Tax Calculator
1. Enter the Asset name. This is just a label — "AAPL shares," "rental property," "Bitcoin" — so you can keep track of which calculation is which if you're running the numbers on more than one holding.
2. Enter the Purchase Price. Use what you originally paid for the asset, including any commissions or fees that were added to your cost basis at the time. Understating your original cost inflates your gain and your tax bill along with it.
3. Enter the Sale Price. Use the actual or expected proceeds from selling the asset, after any transaction fees or commissions are subtracted. The difference between this and your purchase price is your Capital Gain.
4. Select the Holding Period. Choose Short-term if you've owned the asset for one year or less, or Long-term if you've held it for more than a year. This single toggle is often the most consequential input on the page — the same dollar gain can be taxed at your full ordinary income rate as a short-term gain, or at a significantly lower preferential rate once it crosses the one-year mark.
5. Enter Your Annual Income (excluding this gain). This is your other taxable income for the year — salary, self-employment income, and so on — not including the capital gain you're calculating. Because long-term gains stack on top of this number, it's the input that actually determines which capital gains bracket your gain falls into.
6. Select Your Filing Status. Choose Single, Married Filing Jointly, or Head of Household to match how you'll file. This shifts where each capital gains bracket threshold sits.
7. Read Your Results. The calculator shows your Capital Gain, Applicable Tax Rate, Tax Owed, and Net Profit After Tax. For long-term gains, the Long-Term Rate Breakdown chart shows exactly how much of your gain landed in the 0%, 15%, and 20% brackets.
David, a 58-year-old consultant, took an unpaid sabbatical and expected only about $20,000 in part-time income for the year — a rare low-income window before he planned to return to full-time work. He'd been sitting on $30,000 in gains from stock he'd held for three years and wondered whether this was the year to finally sell. Using the calculator with his $20,000 income and single filing status, his taxable income before any gain came to roughly $5,000 after the standard deduction, leaving him well under the income threshold where the 0% long-term capital gains bracket applies. He ran the $30,000 gain through the calculator and the Tax Owed came back as $0 — the entire gain landed inside the 0% bracket. What surprised him was realizing he'd actually budgeted to sell closer to $50,000 in gains that year; running that larger number through the calculator showed a chunk of it spilling past the 0% threshold into the 15% bracket. He scaled his sale back to stay fully inside the tax-free zone and pushed the rest of the sale into the following year instead.
Key Terms
Capital Gain (Gross Gain/Loss)
The difference between what you sold an asset for and what you originally paid for it. A negative result is a capital loss, which can offset gains elsewhere.
Short-Term vs. Long-Term
Short-term applies to assets held 1 year or less (taxed as ordinary income up to 37%). Long-term applies to assets held >1 year and qualifies for preferential rates of 0%, 15%, or 20%.
Applicable Tax Rate
The specific federal rate that applies to your gain once holding period and income are factored in. A large gain can straddle two brackets.
Net Profit After Tax
Your gross gain minus the tax owed — the amount you actually keep after selling.
The Stacking Rule
Long-term capital gains sit directly on top of your other taxable income, filling in above it rather than being taxed as a separate, isolated amount.
Net Investment Income Tax (NIIT)
An additional 3.8% federal tax that can apply to investment income once MAGI crosses $200,000 (single) or $250,000 (married filing jointly).
The 0% Bracket Most Investors Don't Know They Qualify For
Look at the Long-Term Rate Breakdown chart this calculator generates, and you'll notice something most people never think to check: a long-term gain doesn't automatically get taxed at 15% just because that's the rate everyone associates with capital gains. There's a 0% bracket sitting below it, and depending on your other income for the year, some or all of a gain can land there completely tax-free.
The Thresholds Are Wider Than Most People Assume
For the 2025 tax year, single filers with taxable income up to $48,350, and married couples filing jointly up to $96,700, pay 0% federal tax on long-term capital gains — no special account, no obscure loophole, just ordinary tax law. A married couple with $40,000 in combined ordinary income and the standard deduction applied could have well over $50,000 of room left in the 0% bracket before a single dollar of long-term gain gets taxed.
Who Actually Lands in This Window
It's not just people with low salaries. Anyone with a temporarily low-income year qualifies — a sabbatical, a year between jobs, an early-retirement gap before Social Security starts, or a single-earner household where one spouse isn't currently working. These are the exact years financial planners describe as the best time to realize gains that have been sitting untouched for tax reasons.
A Word of Caution Before Assuming This Applies to You
Selling enough to push your total income past the threshold means only the portion above the line gets bumped to 15% — the rest still enjoys the 0% rate, so partial harvesting is always worth considering even if you can't stay under the line entirely.