Capital Gains Tax Explained 2026: What You Owe When You Sell
Quick Answer
Capital gains tax is what you owe the IRS on the profit when you sell a stock, fund, or other investment for more than you paid. The rate depends on how long you held it: short term gains (held one year or less) are taxed at your ordinary income rate, while long term gains (held longer than one year) are taxed at 0%, 15%, or 20% depending on your income bracket. Most U.S. investors pay 15% on long term gains in 2026.
The Basics
A capital gain is simply the difference between what you paid for an investment and what you sold it for. If you bought 100 shares of an index fund at $50 per share and sold them later at $80, your gain is $3,000. The IRS treats that $3,000 differently than wages from your job.
The split between short term and long term is the single biggest factor in how much tax you pay. Hold the investment for more than one year and the day after your holding period crosses that line, the tax rate often drops by half or more. This rule is written into the tax code, not a special deal you have to negotiate.
Short term capital gains are taxed at your ordinary income rate. If your marginal federal bracket is 24%, a $5,000 short term gain costs you about ];,200 in federal tax. The same $5,000 held long term might cost you $750 at the 15% long term rate, a savings of $450 on the exact same profit.
Long term capital gains in 2026 use three brackets. Single filers with taxable income up to $48,350 pay 0%. From $48,350 to $533,400 the rate is 15%. Above $533,400 it climbs to 20%. Married couples filing jointly have higher thresholds: 0% up to $96,700, 15% up to $600,050, and 20% above that.
Your net investment income may also trigger an extra 3.8% Medicare surtax once your modified adjusted gross income passes $200,000 (single) or $250,000 (married filing jointly). On a ];0,000 long term gain above the threshold, that surtax adds $380. Use our tax calculator to estimate your total bill.
Losses work in reverse. If you sold an investment for less than you paid, you have a capital loss. You can use losses to offset gains, and up to $3,000 of leftover losses can offset other income each year. Anything beyond $3,000 carries forward to future tax years. This is the one part of capital gains rules most people leave money on the table with.
The Math
Imagine Sarah, a single filer in 2026 with $90,000 of taxable income, who sold shares for a $20,000 long term gain.
Her taxable income jumps to ];10,000. Since she stays under the $533,400 threshold for the 20% bracket, the entire $20,000 gain falls into the 15% bracket. Federal tax owed on the gain alone is $20,000 x 0.15 = $3,000. After state tax at, say, 5%, another ];,000. Her total bill on that gain is $4,000.
Now compare with her friend Mark, who held his shares for only nine months and sold for the same $20,000 profit. Mark's marginal federal rate is 24%, so he pays $4,800 in federal tax plus ];,000 state. His total bill is $5,800, or ];,800 more than Sarah, just for holding 91 extra days.
One day can be the difference. If Mark waited one more month to cross the one year mark, his bill would have dropped by ];,800 on that $20,000 gain. Run your own sale through our capital gains tax calculator.
| Holding Period | 2026 Rate (single, $90k income) | Tax on $20,000 Gain |
|---|---|---|
| 9 months (short term) | 24% | $4,800 |
| 13 months (long term) | 15% | $3,000 |
| Savings from waiting | 9 percentage points | ];,800 |
Step-by-Step
- Find your cost basis. Pull up your brokerage statement and locate the original purchase price, including any reinvested dividends and commissions. Cost basis is what the IRS considers you "paid," not just the share price.
- Calculate the gain or loss. Subtract your cost basis from your sale proceeds. If you sold 50 shares for $75 each ($3,750 total) and your basis was $40 per share ($2,000), your gain is ];,750.
- Determine the holding period. Count from the day after purchase to the day of sale. If more than one year, the gain is long term. The day you cross the one year mark, the rate changes.
- Report it on Form 8949 and Schedule D. Every sale goes on Form 8949, then totals flow to Schedule D. Your broker sends Form 1099-B, but always verify their numbers. Then use our income tax calculator to see how the gain fits into your overall picture.
Common Mistakes
Forgetting reinvested dividends. If you own a dividend paying fund and reinvested every payout, your cost basis is higher than your original investment. Selling without adjusting basis means you overpay tax. A ];0,000 position with $2,000 of reinvested dividends has a ];2,000 basis, and reporting only ];0,000 inflates your gain by $2,000. At 15%, that costs you $300.
Washing the sale. The wash sale rule disallows a loss if you buy the same security within 30 days before or after the sale. Sell a fund at a ];,500 loss on Monday and accidentally rebuy it the next week, and that loss is gone for tax purposes. Wait 31 days to repurchase, or buy something similar but not identical.
Ignoring state tax. Most states tax capital gains as ordinary income. A 5% state rate on a $50,000 long term gain adds $2,500 to your bill. Eight states have no income tax at all, so your geographic location quietly changes your total tax by thousands. Plan with our payroll tax calculator for a fuller picture.
Frequently Asked Questions
What is the capital gains tax rate for 2026?
Long term capital gains are taxed at 0%, 15%, or 20% in 2026, depending on your taxable income. Short term gains (held one year or less) are taxed at your ordinary income tax rate, which ranges from 10% to 37%. High earners may also owe the 3.8% Net Investment Income Tax.
How does the one year holding period work?
The clock starts the day after you buy and stops on the day you sell. If you buy on March 15, 2025, you must hold until March 16, 2026 to qualify for long term treatment. Selling on March 15, 2026 keeps it short term. The holding period is not based on the calendar year.
When should I harvest losses to offset gains?
Harvest losses in taxable accounts between January and December, but be careful around year end to avoid the wash sale rule. Selling a losing position in mid November and waiting 31 days to repurchase is a clean approach. Pair losses with gains in the same tax year for the largest benefit.
Is the capital gains tax going to change in 2026?
The long term brackets and ordinary income brackets are adjusted each year for inflation, but the structure of capital gains tax has remained stable. The 0%, 15%, and 20% long term rates and the short term treatment as ordinary income are the framework in effect for 2026 filings.
Run the numbers yourself: Tax Calculator