You pay capital gains tax through your annual tax return, either to the IRS or your state tax authority

Capital gains tax is not a separate bill you receive in the mail. Instead, you report the profit from selling an investment on your tax return — either Form 1040 (federal) or your state income tax form — and the tax is calculated as part of your overall tax liability. You then pay it when you file, usually by April 15 of the following year. If you owe a large amount, you can make estimated tax payments throughout the year to avoid a big bill later.

The IRS does not send you a notice telling you how much you owe. You (or a tax preparer) calculate it based on the sale price, your original purchase price, and how long you held the investment. The difference between those two prices is your gain, and the tax rate depends on whether it is a short-term gain (held less than one year) or a long-term gain (held one year or longer).

Key Takeaways

  • You report capital gains on your federal tax return (Form 1040) and your state return if your state has an income tax, using Schedule D to list each sale.
  • Short-term gains are taxed at your ordinary income tax rate; long-term gains are taxed at lower rates (0%, 15%, or 20% federally, depending on your income).
  • Your brokerage or investment platform sends you a Form 1099-B or 1099-S showing the sale price, which the IRS also receives, so the numbers must match your return.
  • If you owe more than $1,000 in federal tax for the year, you should make quarterly estimated payments to avoid penalties.
  • State capital gains taxes vary widely — some states have no income tax, others tax capital gains as ordinary income, and a few have separate capital gains rates.

Understanding short-term versus long-term gains and their tax rates

A short-term capital gain is profit from selling an investment you held for one year or less. It is taxed at your ordinary income tax rate — the same rate as your salary or wages. If you are in the 24% tax bracket, your short-term gains are taxed at 24%. If you are in the 12% bracket, they are taxed at 12%.

A long-term capital gain is profit from selling an investment you held for more than one year. These are taxed at lower rates: 0%, 15%, or 20% federally, depending on your total income for the year. Most people fall into the 15% bracket. The 0% rate applies to lower-income filers, and the 20% rate applies to higher-income filers. These rates do not change with your ordinary income tax bracket — they are fixed regardless of whether you earn $30,000 or $300,000.

The holding period starts the day after you buy and ends the day you sell. If you buy on January 15 and sell on January 15 of the next year, that is exactly one year, and the gain qualifies as long-term. If you sell on January 14, it is short-term.

How to report gains on your tax return

You report capital gains using Schedule D, a form that attaches to your Form 1040. On Schedule D, you list each sale separately: the date you bought, the date you sold, the sale price, your cost basis (what you paid), and the gain or loss. The form automatically calculates your total short-term and long-term gains.

Your brokerage or investment platform (such as Fidelity, Vanguard, Charles Schwab, or your bank's investment arm) sends you a Form 1099-B or Form 1099-S by January 31 showing all the sales you made that year. The IRS receives a copy of this form too, so the numbers on your tax return must match. If you report a different sale price or cost basis than what appears on the 1099-B, the IRS will flag it.

If you sold only one or two investments and the gains are small, you may be able to report them directly on Form 1040 without Schedule D, depending on your situation. A tax preparer or tax software can tell you whether you need the full form. If you sold many investments or have losses to report, Schedule D is required.

Handling losses and offsetting gains

If you sold an investment at a loss, you can use that loss to reduce your taxable gains. This is called tax-loss harvesting. If you had $5,000 in gains and $2,000 in losses, your net gain is $3,000, and you pay tax only on that $3,000.

If your losses exceed your gains in a given year, you can deduct up to $3,000 of the excess loss against your ordinary income (wages, salary, interest, and so on). Any losses beyond $3,000 carry forward to future years, meaning you can use them to offset gains or income in the years ahead. This carryforward has no time limit — you can use it whenever you have gains to offset.

Losses must be reported on Schedule D as well. You list both gains and losses, and the form calculates the net. The IRS uses this net figure to determine your tax.

State capital gains taxes and where you owe

Capital gains taxes at the state level vary widely. Nine states have no income tax at all (Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, Wyoming, and New Hampshire), so residents of those states owe no state capital gains tax. Most other states tax capital gains as ordinary income — meaning your capital gains are added to your wages and taxed at your state income tax rate, which ranges from about 1% to 13% depending on the state.

A few states have separate capital gains taxes. Washington State, for example, has a 7% capital gains tax on long-term gains above a certain threshold, even though it has no ordinary income tax. California taxes capital gains as ordinary income but at rates up to 13.3%. New York taxes them as ordinary income at rates up to 10.9%.

You owe state tax in the state where you live on December 31 of the tax year, not the state where you bought the investment or where the company is headquartered. If you moved during the year, you may owe tax to two states, and you will need to file part-year returns in each.

Making estimated tax payments if you owe a large amount

If you expect to owe $1,000 or more in federal tax for the year (including capital gains tax), the IRS expects you to make estimated quarterly payments throughout the year rather than waiting until April 15. These payments are due on April 15, June 15, September 15, and January 15 of the following year.

You calculate estimated tax using Form 1040-ES, which walks you through estimating your income, deductions, and tax for the year. You then divide that total by four and pay one quarter each quarter. You can pay online through IRS.gov, by mail, or through your bank's bill-pay system.

If you do not make estimated payments and owe a large amount at tax time, the IRS will charge you a penalty and interest on the unpaid amount. The penalty is small if you are only slightly under, but it grows if you owe significantly more than you paid. Making quarterly payments avoids this penalty and spreads the cost across the year.

What your brokerage reports and how to verify it

Your brokerage is required by law to send you a Form 1099-B (for stocks, bonds, and mutual funds) or Form 1099-S (for real estate) showing every sale you made. The form lists the sale price and, in many cases, your cost basis — the price you paid. However, cost basis reporting is not always accurate, especially if you bought the investment years ago or at a different brokerage.

You should verify the cost basis yourself using your purchase confirmations, statements, or records. If the 1099-B shows the wrong cost basis, you can correct it on your tax return. The IRS will not automatically reject your return if the 1099-B and your Schedule D differ, but you should have documentation to back up your numbers. Keep purchase receipts, statements, and sale confirmations for at least three years in case the IRS asks questions.

If you received a 1099-B but did not actually sell anything (for example, if the form is for a different account), contact your brokerage when ready to request a corrected form. Do not file your tax return with incorrect information.

Frequently Asked Questions

Do I have to pay capital gains tax the year I sell, or can I wait until I file my return?

You do not owe the tax until you file your return, usually by April 15 of the following year. However, if you owe $1,000 or more, you should make estimated quarterly payments during the year to avoid penalties. The full amount is due when you file.

What if I sold an investment but have not received a 1099-B yet?

Brokerages must send 1099-Bs by January 31. If you have not received one by early February, contact your brokerage. You can still file your return using your own records, but the IRS will also receive the 1099-B, so the numbers must match. Do not delay filing waiting for the form.

Can I avoid capital gains tax by holding an investment longer?

Holding longer changes the tax rate — long-term gains are taxed at lower rates than short-term gains — but you still owe tax when you sell. You cannot avoid the tax by waiting; you can only reduce the rate. Once you sell, the tax is due.

What happens if I sell an investment at a loss?

You report the loss on Schedule D, and it offsets any gains you have. If losses exceed gains, you can deduct up to $3,000 against your ordinary income. Any excess loss carries forward to future years with no time limit.

Do I owe capital gains tax on investments in a 401(k) or IRA?

No. Investments inside a 401(k), traditional IRA, or Roth IRA are not subject to capital gains tax when you sell them within the account. You only pay tax when you withdraw money from the account (and rules vary by account type). This is one major advantage of saving through these accounts.