When Diane sold her Apple stock in October, she was thrilled. She’d bought 50 shares eighteen months earlier for $8,400 and sold them for $14,200 — a $5,800 profit. She immediately started mentally planning what to do with the windfall, assuming she’d keep most of it.
Her tax return told a different story. Between the capital gains tax, the way the gain interacted with her other income, and the Net Investment Income Tax she hadn’t known about, her actual after-tax gain was closer to $4,100.
She hadn’t made any mistakes. She’d simply never understood how capital gains tax actually works — which is a different question from knowing the rates exist.
The single most important variable: how long you held it
Before anything else, the IRS asks one question about every investment gain: how long did you own it?
If you held the asset for one year or less, the gain is short-term. Short-term gains are taxed at ordinary income rates — the same rates that apply to your salary, freelance income, and business profit. Depending on your tax bracket, that could be 10%, 12%, 22%, 24%, 32%, or 35%.
If you held it for more than one year, the gain is long-term. Long-term gains qualify for preferential rates — 0%, 15%, or 20% depending on your total income — that are significantly lower than ordinary income rates for most taxpayers.
That single distinction — one year and one day versus one year exactly — can mean the difference between paying 22% and paying 15% on the same dollar of profit. For a $50,000 gain, that’s $3,500 in additional tax for selling one month too early.
Long-term capital gains rates — and the 0% bracket most people don’t know about
Most people know that long-term capital gains are taxed at lower rates. Fewer know that there’s a 0% rate available to taxpayers whose total taxable income falls below certain thresholds.
For 2024, a single filer with taxable income up to about $47,025 pays 0% on long-term capital gains. A married couple filing jointly pays 0% up to about $94,050. This doesn’t mean the gain disappears — it means the rate applied to it is zero.
Above those thresholds, the 15% rate applies for most middle and upper-middle income taxpayers. The 20% rate kicks in at higher income levels — roughly $518,900 for single filers and $583,750 for married filing jointly in 2024.
| Filing status | 0% rate (up to) | 15% rate (up to) | 20% rate (above) |
|---|---|---|---|
| Single | $47,025 | $518,900 | $518,900+ |
| Married filing jointly | $94,050 | $583,750 | $583,750+ |
| Head of household | $63,000 | $551,350 | $551,350+ |
The stacking effect — why your other income matters
This is the part that catches most people off guard, and it’s why two investors can sell the same asset for the same gain and pay completely different tax rates.
Long-term capital gains don’t sit in isolation on your return. They stack on top of your ordinary income. The IRS first counts your wages, business income, and other ordinary income. Then it places your long-term gains on top of that total. The rate applied to the gains depends on where that combined amount falls in the bracket structure.
Here’s a concrete example: a single filer with $35,000 in ordinary income and a $20,000 long-term capital gain. Their ordinary income puts them below the $47,025 threshold for the 0% rate. The first $12,025 of the gain ($47,025 minus $35,000) falls in the 0% bracket. The remaining $7,975 of the gain falls in the 15% bracket. Their total capital gains tax is about $1,196 — not zero, but significantly less than if the gain were short-term.
Change the scenario: same person, but they sold after only ten months. The entire $20,000 gain is short-term, added to ordinary income, and taxed at 22%. Capital gains tax: $4,400. Same asset, same profit, different holding period — a $3,204 difference.
Interactive estimate: short-term vs. long-term
The Net Investment Income Tax — the layer most people miss
Investors with higher income face an additional 3.8% surtax on net investment income once modified adjusted gross income exceeds $200,000 for single filers or $250,000 for married filing jointly. This is called the Net Investment Income Tax, and it applies on top of the standard capital gains rates.
For a high-income investor in the 20% long-term capital gains bracket, the effective rate including NIIT is 23.8%. For someone in the 15% bracket whose income pushes above the NIIT threshold, the effective rate is 18.8%. This tax applies to capital gains, dividends, interest income, and passive income from investments.
Diane’s situation from the beginning of this article included NIIT — her total income for the year pushed above the threshold, so her $5,800 gain was subject to both the 15% long-term rate and the 3.8% NIIT, bringing her effective rate on the gain to 18.8%.
Special situations worth knowing
Real estate. Selling a primary residence is one of the most valuable tax benefits in the code. If you’ve owned and lived in the home for at least two of the past five years, you can exclude up to $250,000 of gain from tax ($500,000 for married couples). Investment properties don’t qualify for this exclusion and come with an additional complexity: depreciation recapture. Any depreciation you claimed on the property over the years is “recaptured” at a 25% rate when you sell, separate from the standard capital gains calculation.
Capital losses. Losses on investments offset gains. If your losses exceed your gains for the year, up to $3,000 of the net loss can offset ordinary income, with the remainder carried forward to future years indefinitely. Strategic tax-loss harvesting — selling underperforming investments to generate losses that offset gains elsewhere — is one of the most commonly used year-end tax planning strategies.
Frequently asked questions
Is the long-term capital gains rate always 15%? No. It can be 0%, 15%, or 20% depending on your total taxable income, and high earners may also owe the 3.8% NIIT on top.
Does holding exactly one year qualify for long-term rates? No — you must hold for more than one year. Exactly one year is still short-term. The day count matters.
Can I use investment losses to offset ordinary income? Yes, but only up to $3,000 per year. Any excess carries forward to future years.
Does the capital gains rate apply to the entire gain or just the portion above a threshold? The rate is applied to the gain itself, but where that gain falls in the bracket structure depends on your total income. The gain is “stacked” on top of your ordinary income, and the applicable rate is determined by where that stacked total lands.