Capital Gains Tax on Investments Explained
A capital gain is only taxed when you sell, and how long you held the asset can cut your rate roughly in half. Here's how the system actually works.
Don't have time? Here's what you need to know:
- 1Capital gains are only taxed when realized — an unrealized gain on a holding you keep is never taxed.
- 2Holding more than one year converts a short-term gain (ordinary rates) into a long-term gain taxed at 0/15/20%.
- 3Long-term rates depend on your taxable income, and high earners owe an extra 3.8% Net Investment Income Tax.
- 4Losses offset gains plus up to $3,000 of ordinary income per year, with the excess carried forward indefinitely.
Nothing Is Taxed Until You Sell
A capital gain is the profit you make when you sell an asset for more than you paid for it. The crucial word is sell. An ETF that doubles in value creates an unrealized gain that sits on paper, untaxed, for as long as you hold it. Only when you sell does the gain become realized — and only then does it appear on your tax return. This single feature gives long-term investors enormous control over their tax timing.
Your gain is the difference between your sale proceeds and your cost basis — what you paid, including reinvested dividends and commissions. If you sell for less than your basis, you have a capital loss, which is not a wasted event: losses offset gains and can shelter ordinary income, a strategy known as tax-loss harvesting. Capital losses are one of the few genuinely useful side effects of a down market.
The One-Year Holding Period Is the Whole Game
The tax code splits capital gains into two buckets based on how long you held the asset. Hold for one year or less and the gain is short-term, taxed at your ordinary-income rate — the same rate as your salary, which can be quite high. Hold for more than one year and it becomes a long-term gain, taxed at the preferential federal rates of 0%, 15%, or 20% depending on your taxable income.
The gap between those two treatments is the single largest lever most investors have. For someone in a higher bracket, flipping a position one day before the one-year mark instead of one day after can roughly double the tax on that gain. This is a core reason buy-and-hold investing is tax-efficient almost by accident: simply holding longer converts expensive short-term gains into cheap long-term ones.
| Short-term gain | Long-term gain | |
|---|---|---|
| Holding period | 1 year or less | More than 1 year |
| Federal tax rate | Ordinary income rates | 0%, 15%, or 20% |
| Rate depends on | Your full income | Your taxable income tier |
| Typical use case | Active trading | Buy-and-hold investing |
Tip: Count the holding period from the day after you buy to the day you sell. "More than one year" means at least one year and one day — a position bought on March 10 must be sold on March 11 of the next year or later.
Your Income Decides Which Long-Term Rate Applies
Long-term capital-gains rates are not flat. They sit at 0%, 15%, or 20%, and which one you pay depends on your total taxable income for the year. Lower-income investors can fill the 0% bracket, paying literally nothing in federal tax on long-term gains up to a threshold; middle-income investors generally pay 15%; and only the highest earners reach 20%. The IRS adjusts the income breakpoints every year, so always check current figures rather than relying on a number you saw once.
There's also a surtax to know about. High earners owe the 3.8% Net Investment Income Tax on capital gains and other investment income once modified adjusted gross income crosses the IRS threshold. Stacked on a 20% long-term rate, that pushes the effective federal rate on gains toward 23.8% for top earners. State income tax, where it applies, sits on top of all of this.
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Losses, Timing, and the Step-Up at Death
Because gains are only taxed when realized, you control the timing. You can harvest losses to offset gains within the same year; if losses exceed gains, you can deduct up to $3,000 against ordinary income annually and carry the rest forward indefinitely. You can also sit in the 0% long-term bracket in a low-income year and deliberately realize gains tax-free — a tactic sometimes called gain harvesting.
The most powerful timing tool of all is one you never trigger yourself: the step-up in basis at death. When an heir inherits appreciated assets, the cost basis generally resets to the market value on the date of death, erasing the embedded capital gain entirely. This is a major reason long-term investors are often advised never to sell highly appreciated positions purely to chase a small fee saving — the tax cost of selling can dwarf the benefit. Rules here are intricate, so consult a tax professional for estate planning.
Important: Watch the wash-sale rule when harvesting losses: if you rebuy the same or a substantially identical security within 30 days before or after the sale, the loss is disallowed. Swap to a similar-but-distinct fund instead.
Frequently Asked Questions
How much is capital gains tax?
It depends on how long you held the asset and your income. Short-term gains (held one year or less) are taxed at your ordinary-income rate. Long-term gains (held more than a year) are taxed at 0%, 15%, or 20% federally, based on your taxable income, plus a possible 3.8% surtax for high earners. Check current IRS income breakpoints, which change yearly.
Do I pay capital gains tax if I don't sell?
No. Capital gains tax applies only to realized gains — gains you lock in by selling. An investment that rises in value but stays in your account creates an unrealized gain that is never taxed until you sell. This is what lets buy-and-hold investors defer tax for decades.
How can I legally reduce capital gains tax?
Hold investments longer than a year to get long-term rates; harvest losses to offset gains; realize gains in low-income years when you may fall in the 0% bracket; use tax-advantaged accounts like a Roth IRA; and let heirs benefit from the step-up in basis. A tax professional can tailor these to your situation.
Are capital gains taxed by states too?
Often, yes. Most states with an income tax treat capital gains as ordinary income and tax them at their regular state rate, with no preferential long-term rate. A handful of states have no income tax at all. State tax is separate from and additional to the federal capital-gains tax.
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Alex Harrington
CFA Level II Candidate, Finance & Economics
Alex Harrington is an independent ETF researcher and personal finance writer with over 8 years of experience analyzing exchange-traded funds. A CFA Level II candidate with a background in economics, Alex has reviewed 800+ ETFs and helped thousands of beginners build their first investment portfolios through clear, jargon-free education.
This content is for educational purposes only and does not constitute financial advice. Past performance does not guarantee future results. Consult a licensed financial advisor before making investment decisions.