How Capital Gains Are Really Taxed

Ask most investors how their capital gains get taxed and you’ll hear some version of “fifteen percent, I think.” It’s a reasonable guess, and it’s frequently wrong — sometimes expensively, sometimes in your favor. The actual rule is more interesting, and once you see it, a set of planning opportunities opens up that most people walk past every year.

Here it is in one sentence: long-term capital gains are stacked on top of your ordinary income, and only the portion of the gain that lands above each threshold pays the higher rate.

First, the distinction that changes everything: how long did you hold it?

Before any stacking happens, the calendar decides which set of rules applies to your gain.

• Short-term gains — assets held one year or less — get no special treatment at all. They’re simply added to your ordinary income and taxed at your regular rates, which run from 10% up to 37%. A short-term gain behaves exactly like a bonus from work: it stacks into your ordinary income and can push more of that income into higher brackets.
• Long-term gains — assets held more than one year — along with qualified dividends, get their own lower rates: 0%, 15%, or 20%.

The gap between those two treatments is enormous. The same $50,000 profit can face a 37% top rate or a 0% rate depending on nothing more than the holding period and where it lands in your stack. This is why “should I sell now or wait until the one-year mark?” is one of the most valuable questions an investor can ask — and one of the easiest to answer wrong in a hurry.

How the stacking actually works

The IRS runs the calculation in two passes, and the order is the whole story.

Pass one: ordinary income is taxed first. Your wages, interest, IRA withdrawals, pension income, and any short-term gains — minus your deductions — are calculated and taxed as if your long-term gains didn’t exist. This is the part that surprises people: a large long-term gain does not push your ordinary income into a higher ordinary bracket.

Pass two: the gains are layered on top. Now the IRS adds everything together — ordinary income plus long-term gains and qualified dividends — to decide which rate applies to the gains. The gain fills upward from wherever your ordinary income stopped. Different slices of the same gain can be taxed at different rates.

A worked example

Take a single filer in 2026 with $40,000 of ordinary taxable income and a $20,000 long-term gain — $60,000 of total taxable income.

The $40,000 of ordinary income is taxed at ordinary rates, largely in the 10% and 12% brackets. Then the gain stacks on top. For a single filer, the 0% capital gains bracket runs up to $49,450 of taxable income — which leaves $9,450 of room above that $40,000 of ordinary income. So the first $9,450 of the gain is taxed at 0%. The remaining $10,550 spills into the 15% band and is taxed at 15%.

Two things are worth noticing. First, this taxpayer’s effective rate on the gain was under 8% — not the 15% they’d have assumed. Second, and more useful: suppose the same person sold in a year with little or no ordinary income — an early-retirement gap year, say. Far more of that gain, possibly all of it, would have been taxed at 0%. The gain didn’t change. The stack underneath it did.

The 2026 thresholds

These figures apply to taxable income — that’s your income after the standard or itemized deduction, not your gross pay. In 2026 the standard deduction is $16,100 for single filers and $32,200 for married couples filing jointly. That deduction comes off first — so your gross pay can sit well above these numbers while your taxable income still lands in a lower band. Reading these as limits on gross income is the most common mistake we see.

Why this matters more than it sounds

The stacking rule isn’t trivia. It means the tax on a gain is largely determined by what else is happening in your income that year — and unlike the market, that’s something a plan can control.

• The gap years are golden. The stretch between retiring and starting Social Security or required distributions is often the lowest-income period of an entire adult life. Ordinary income is low, which means the room under the 0% capital gains threshold is at its widest it will ever be. Gains realized in those years can be extraordinarily cheap — sometimes free.
• Gain harvesting is a real strategy. If you’re sitting inside the 0% band, you can sell a position and buy it right back. You pay no federal tax on the gain, and your cost basis resets higher — which lowers the tax on every future sale. (Note that the wash-sale rule restricts loss harvesting, not gain harvesting.)
• Roth conversions and gain harvesting compete for the same room. Both strategies want to use the space in your lower brackets, and a conversion adds ordinary income — which lifts the entire stack and can push gains from the 0% band into the 15% band. Doing both in the same year without running the numbers is how a good idea turns expensive. Which one should use the room this year is exactly what a plan is for.
• When you sell can change what it costs. Splitting a large sale across two tax years, or waiting until you pass the one-year mark, can move real money — but only if you know what the rest of that year’s income looks like first.

The fine print worth knowing

• The 3.8% surtax. Higher earners may owe the Net Investment Income Tax on gains and other investment income once modified adjusted gross income passes $200,000 (single) or $250,000 (married filing jointly). It’s calculated separately and sits on top of the rates above — so a 15% gain effectively costs 18.8%, and a 20% gain 23.8%. These thresholds are set by statute and are not adjusted for inflation, so they capture more households every year.
• Not every gain gets the friendly rates. Collectibles can be taxed up to 28%. And on real estate, the part of your gain that comes from depreciation you already deducted — called unrecaptured Section 1250 gain — can be taxed up to 25%.
• States often disagree. Many states tax capital gains as ordinary income or apply their own rules entirely, so the federal answer is only part of your answer.
• Losses are a tool. Capital losses offset capital gains of the same type first, then up to $3,000 of ordinary income a year. Anything left over carries forward indefinitely. A bad year’s losses are a real asset in future years.

If you’re holding an appreciated position — a concentrated stock, a rental property, a business interest, or simply a long-held fund with a low basis — the question is rarely whether to sell. It’s which year, in what size, and against what else. That’s a planning question, and it’s one we work through with clients every year.