What is capital gains tax? A plain-English guide

Key takeaways

• You owe the tax when you sell, not while the price is only on paper.
• A $50,000.00 sale with a $10,000.00 basis is a $40,000.00 gain.
• For a single filer with $30,000 of other taxable income, $19,450.00 of that gain is taxed at 0% and $20,550.00 at 15%.
• Federal tax on the gain is $3,082.50. NIIT is $0.00.
• The other guides own the rate tables, the 1-year line, and the full formula.

Before you start

Capital gains tax

Capital gains tax is the federal tax on profit from selling a capital asset. People also type capital gain tax for the same tax.

Capital asset

A capital asset is property you own for investment or personal use, and inventory you hold for sale to customers is not one.

Basis

Basis is what you paid for the asset, plus purchase fees.

Capital loss

A capital loss is a sale price below your basis. The $3,000 yearly limit lives on the [loss carryover guide](/blog/capital-loss-carryover/).

Do I pay capital gains tax if I only hold?

You owe capital gains tax when you sell, and you do not owe it while you still hold the asset, so a gain that exists only on a statement is unrealized and it is not taxed yet, and a higher quote during the year does not create a capital gain by itself because the bill belongs to the year of the sale.

Who pays capital gains tax, and when?

A person who sells a capital asset in the United States reports the gain on the return for that year, and the tax is part of that return rather than a separate bill on the sale date, while a large sale requires estimated tax when withholding will not cover the bill, and this page does not compute the voucher (Topic 409 and Publication 505).

How do I calculate a capital gain?

Subtract basis from the sale price, so a sale at $50,000.00 with a basis of $10,000.00 is a $40,000.00 gain, and the dates in the worked example are 15 January 2024 and 15 June 2026, which makes the gain long-term.

The seller in this example is single with $30,000 of taxable income before the gain, federal tax on the gain is $3,082.50, NIIT is $0.00, state tax is left out, and the calculate guide keeps the full order of the math.

What separates a short-term gain from a long-term gain?

A sale on the 1-year anniversary is still short-term, and the next day is long-term, while the holding-period guide is the home for that clock, including the trade date and the day after you buy.

Which rate applies to me?

A long-term gain uses 0%, 15%, or 20% in 2026, a short-term gain uses ordinary rates from 10% to 37%, and your other taxable income fills the brackets first so the gain is taxed only on the room that is left.

For a single filer the 0% ceiling is $49,450, for married filing jointly the 0% ceiling is $98,900, and the 2026 rates guide keeps the full ceilings while this page does not print the ordinary bracket schedule.

What is the 0% capital gains bracket?

In the worked example, $19,450.00 of the $40,000.00 gain is taxed at 0% and $20,550.00 is taxed at 15%, which is why the federal tax is $3,082.50, because the 0% slice is the room between $30,000 of taxable income and the $49,450 ceiling.

The 0% bracket guide explains who still has that room, and this page shows only this one split.

Are gains inside an IRA or 401(k) taxed?

Trades inside a traditional IRA or 401(k) are not capital-gains events, withdrawals from those accounts are taxed as ordinary income rather than as capital gains, and the IRA guide is the home for that rule.

Do I pay it on a car?

A gain on personal-use property is taxable, and a loss is not deductible, and most cars sell for less than the owner paid, so a typical car sale creates no deductible loss and no tax (Publication 550).

A home sale may qualify for the exclusion on the home sale guide, crypto is taxed when you sell, swap, or spend it on the crypto guide, and a fund sale uses the day you bought the shares while a capital-gain distribution on Form 1099-DIV follows the fund reporting.

Do states tax capital gains?

Many states tax a capital gain even when the federal rate on that slice is 0%, the state overview is the home for those differences, and a federal result of $0 does not mean the state bill is $0.

Which form will I receive?

A broker reports a stock sale on Form 1099-B, a real-estate closing produces Form 1099-S, and a digital-asset sale produces Form 1099-DA when the payer knows the details, so check the dates and the basis on the form before you copy them.

You report the sale on Form 8949, Schedule D totals those lines, and the Schedule D guide walks through that order, while this page does not fill in the forms.