Capital gains: short-term, long-term, and the tax gap

A capital gain is the profit you make when you sell an investment for more than you paid. Buy a share of an index fund for $200, sell it later for $300, and you have a $100 capital gain. The IRS wants a cut of that $100. How big a cut depends almost entirely on one thing: whether you held the investment for one year or less, or for longer than a year. Get past that one-year mark and the tax rate on the same gain can fall by more than half.

Short-term vs long-term, and why the calendar matters

The line is exactly one year. Hold an investment for one year or less and any profit is a short-term capital gain, taxed as ordinary income at your regular rate, which runs up to 37% for the highest earners. Hold it for longer than a year, meaning a year and a day or more, and the profit becomes a long-term capital gain, taxed at a separate, lower set of rates: 0%, 15%, or 20%.

Same investment, same $100 of profit. The only difference is the date on the sell ticket. The tax code is paying you to be patient. It taxes a quick flip like the wages from your job and gives a discount to money you left invested for more than a year.

The long-term rates: 0%, 15%, or 20%

Long-term gains have their own brackets, and they are based on your total taxable income, not just the gain. For a single filer in 2025, the first roughly $48,350 of taxable income sits in the 0% long-term bracket. Above that, up to about $533,400, long-term gains are taxed at 15%. Past that, the rate is 20%. Married couples filing jointly get wider bands: 0% up to about $96,700, then 15%, then 20% above roughly $600,050.

Compare that to the ordinary brackets your short-term gains and your paycheck fall into: 10%, 12%, 22%, 24%, 32%, 35%, and 37%. The same dollar of profit can be taxed at 22% as a short-term gain or 15% as a long-term gain, and for plenty of young earners the long-term rate is 0%. If you want to see which ordinary bracket your income lands in, run it through our tax bracket calculator, and the taxes guide walks through how the brackets stack.

A worked example: $5,000 of profit

Say you bought a stock or fund and you are sitting on a $5,000 gain. Your other income puts you in the 22% ordinary bracket, which is typical for a single person earning somewhere in the $50,000s. Here is what the tax bill looks like depending on when you sell.

Sell early and you owe $1,100, which is 22% of $5,000. Wait past the one-year mark and you owe $750, which is 15% of $5,000. Same $5,000 profit, but holding for one extra day on the calendar keeps an extra $350 in your pocket. That $350 is a guaranteed, tax-free return for doing nothing but waiting, and it scales with the size of the gain. On a $50,000 gain the same gap would be $3,500.

Some people pay 0% on their gains

The 0% long-term bracket is real, and it is wider than most people expect. A single filer in 2025 with taxable income at or below about $48,350 pays nothing on long-term capital gains. That figure is taxable income, which is your total income minus the standard deduction of $15,000 for a single filer. So a single person could earn around $63,000 in gross income, take the standard deduction, and still have room for long-term gains taxed at 0%.

This matters most in lower-income years: a year between jobs, a year in grad school, the first year of a business when profit is thin. Selling winners you have held more than a year during a low-income year can mean harvesting real gains and owing zero federal tax on them. The strategy of deliberately selling to use up that 0% band even has a name, gain harvesting, and it is the friendly cousin of tax-loss harvesting.

You owe nothing until you sell

Here is the part that trips up new investors. A gain on paper is not taxed. If your $200 share is now worth $500 and you have not sold it, that $300 is an unrealized gain, and the IRS does not touch it. You can hold an investment for thirty years while it climbs tenfold and never pay a cent of capital gains tax, as long as you never sell.

The tax event is the sale. The moment you sell, the gain becomes realized, and it lands on that year's tax return. This is why long-term buy-and-hold investing is so tax-efficient: every year you do not sell is a year the government does not get its cut, and the full balance keeps compounding for you instead. It is also why selling and rebuying constantly is expensive. Each sale can trigger a tax bill that a patient holder simply never pays.

What happens when you lose money

Capital losses are the mirror image of gains, and the tax code lets you use them. First, losses offset gains of the same type: short-term losses cancel short-term gains, long-term losses cancel long-term gains, and any leftover crosses over. If your losses for the year exceed your gains, you can deduct up to $3,000 of the excess against your ordinary income, the wages from your job included.

Anything beyond that $3,000 does not vanish. It carries forward to future years, where you keep using $3,000 a year against ordinary income until the loss is used up, or you apply it against future gains. A $10,000 net loss, for example, deducts $3,000 this year, $3,000 next year, $3,000 the year after, and the final $1,000 in year four. Realized losses are one of the few times the market handing you a bad outcome also hands you a tax break.

The short version

• Hold past one year. Long-term rates of 0%, 15%, or 20% beat the ordinary rates of up to 37% that short-term gains pay.
• Watch the date. One day short of a year and your gain is taxed as ordinary income. The anniversary is worth waiting for.
• Selling is the trigger. Unrealized gains are not taxed. You decide when the bill comes due by choosing when to sell.
• Losses are usable. They offset gains and up to $3,000 of ordinary income a year, with the rest carrying forward.

FAQ

When is my capital gains rate actually 0%?

When the gain is long-term, meaning you held the investment more than a year, and your total taxable income is low enough. For a single filer in 2025 that is taxable income at or below about $48,350, which after the $15,000 standard deduction means roughly $63,000 of gross income. Married couples filing jointly get the 0% rate up to about $96,700 of taxable income. Short-term gains never qualify for 0%, because they are taxed at your ordinary rate no matter how low your income is.

Do I owe tax if I never sell?

No. A gain is only taxed once you sell and realize it. If your investment rises in value but you keep holding it, that profit is an unrealized gain and the IRS does not tax it, this year or any year you keep holding. The one exception to watch is dividends, which are taxable in the year you receive them even if you never sell a single share. Price gains, though, stay tax-free until the day you cash out.

What happens with capital losses?

You put them to work. Losses first cancel out gains of the same type, then cross over to cancel the other type. If you end the year with more losses than gains, you can deduct up to $3,000 of the excess against your ordinary income, and anything left over carries forward to future tax years. A losing investment you sell can lower your tax bill, which softens the blow and is the whole idea behind tax-loss harvesting.

Does selling inside a Roth IRA or 401(k) trigger capital gains tax?

No. Capital gains rules apply to taxable brokerage accounts. Inside a Roth IRA, a traditional IRA, or a 401(k), you can buy and sell as often as you like without owing capital gains tax on the trades. Roth withdrawals in retirement come out completely tax-free, and traditional accounts are taxed as ordinary income only when you withdraw. The one-year holding rule and the 0/15/20 brackets are a concern only for investments you hold in a regular, taxable account.