0% Long-Term Capital Gains Rate

The 0% long-term capital gains rate is the federal rate applied to adjusted net capital gain, meaning long-term capital gains plus qualified dividends, to the extent that income falls below a threshold measured in taxable income. Internal Revenue Code section 1(h)(1) reaches it in an unusual way: the tax "shall not exceed" the sum of several components, and subparagraph (B) applies "0 percent" to the gain below the threshold. The Internal Revenue Service calls that threshold the maximum zero rate amount, under section 1(j)(5)(B), and publishes it each autumn.

The common name for the same thing, "the 0% bracket", is worth unpicking because the shorthand misleads people in a specific way. Ordinary brackets describe where your last dollar lands. This threshold instead describes how much of a gain gets the zero rate before the rest moves to 15%, and it is perfectly normal for one sale to be split across both. For 2026 the ceiling is $49,450 of taxable income for single filers, $98,900 for married couples filing jointly, $66,200 for heads of household, and $49,450 for a married person filing separately.

The mechanism nobody explains is the stacking order, and it decides everything. Section 1(h)(1)(A) computes the ordinary tax on taxable income reduced by the net capital gain, which is another way of saying that wages, pensions, interest and retirement withdrawals fill the rate schedule from the bottom, and the long-term gain is layered on top of them. So the room available at 0% is not the whole ceiling. It is the ceiling minus whatever ordinary taxable income is already occupying the space below it.

The second thing to hold onto is that the ceiling is a taxable income figure, not adjusted gross income. Taxable income is what is left after the standard deduction or itemized deductions, so a filer taking the standard deduction can have gross income higher than the ceiling by roughly the amount of that deduction and still have gain taxed at 0%. Confusing the two measures is the single commonest way people conclude the rate cannot possibly apply to them.

Third, the gain is counted in its own test. Realizing a large gain raises taxable income, which consumes the remaining room, so the window is partly self-limiting. Beyond the ceiling the rate steps to 15% and, above a second threshold, to 20%. Nothing about the earlier slice is undone; the higher rate applies only to the excess.

Two limits are worth stating plainly. The zero rate is a rate under section 1(h) of the federal income tax, and it does not switch off anything keyed to a different measure: realizing the gain still raises adjusted gross income, which is the input to income-tested items such as marketplace health insurance subsidies, Medicare premium surcharges and the taxation of Social Security benefits. And state income tax is computed separately. Many states tax capital gain as ordinary income and offer no equivalent zero rate, so a gain that costs nothing federally can still produce a state bill; the state revenue department is the place to check.

The calculation runs in a fixed order. First, work out taxable income for the year including the gain. Second, separate the adjusted net capital gain, meaning net long-term capital gain plus qualified dividends, from everything else. Third, stack the ordinary income underneath, so the room left is the ceiling minus that ordinary taxable income. Fourth, apply 0% to the gain that fits in the room, 15% to the next slice, and 20% above the second threshold.

A hypothetical, with round stand-in numbers chosen so the arithmetic stays checkable even as the published ceiling moves: suppose the 0% ceiling for a single filer is $50,000 of taxable income. Devon has $38,000 of ordinary taxable income after his deductions and realizes a $20,000 long-term capital gain. The ordinary income fills the space from zero to $38,000, leaving $12,000 of room under the ceiling. So $12,000 of the gain is taxed at 0% and the remaining $8,000 is taxed at 15%, producing $1,200 of federal tax on a $20,000 gain, an effective rate of 6%.

Two lessons fall out of that example. Devon could have realized $12,000 of gain at no federal cost at all, and every dollar of ordinary income he adds, a bonus or a retirement withdrawal, takes a dollar of that room away.

Pros

• A genuine 0% federal rate, not a deferral, on the portion of gain that fits under the ceiling.
• Qualified dividends ride the same schedule, so a low-income year can pass dividend income through untaxed as well.
• The threshold is generous relative to gross income, because it is measured after the standard deduction.
• Low-income and transition years, such as a gap between jobs or the years between retiring and claiming Social Security, create the room naturally.

Cons

• The room is easy to overestimate, because ordinary income fills it first and people forget to subtract it.
• It disappears as it is used: a large gain pushes its own later slice to 15%.
• It is a federal rate only. State income tax is computed separately, and many states have no equivalent zero rate.
• The gain still raises adjusted gross income, so it can reduce income-tested benefits even in a year when the tax on it is zero.
• For estates and trusts the ceiling collapses to a few thousand dollars, so retaining gains inside a trust rarely reaches the rate.