What does the 20% long-term capital gains rate apply to, and who pays it?

The top long-term capital gains rate of 20% applies only to high earners. In 2025 it kicks in once taxable income exceeds roughly $533,400 for single filers or $600,050 for married filing jointly; below that the rate is 15%, and lower-income filers pay 0%. Importantly, the 3.8% Net Investment Income Tax usually stacks on top for people at this level, pushing the effective federal rate on big gains to 23.8%. Because these are graduated brackets, only the portion of gains above each threshold is taxed at the higher rate – not your whole gain. This is why large, lumpy sales (a business exit, a concentrated stock position) benefit from spreading across multiple tax years or pairing with harvested losses to stay in a lower band. Model a big sale at wealthserene.com/tools/capital-gains.