One year is the line that changes everything
Sell an investment you’ve held for one year or less, and the profit is a short-term capital gain, taxed exactly like ordinary income — the same brackets that apply to your salary. Hold it past one year, and the profit becomes a long-term capital gain, taxed at meaningfully lower preferential rates: 0%, 15%, or 20% depending on your income. The math above shows both stacked on your actual income, so you can see the real dollar difference a single day’s holding period can make.
Why gains “stack” instead of just applying a flat rate
Capital gains don’t get taxed in isolation — they stack on top of your ordinary income to determine which bracket they land in. Short-term gains stack first, taxed at your ordinary marginal rates. Long-term gains then stack on top of your ordinary income plus short-term gains, taxed at the long-term rates for whatever bracket that combined total falls into. This is why the same $25,000 long-term gain can be entirely tax-free for one person and partially taxed at 15% or 20% for another — it depends entirely on what income it’s stacking on top of.
The 0% bracket is real, and often overlooked
Long-term gains that fall within the 0% bracket — up to $49,450 of total taxable income for single filers, $98,900 for married filing jointly in 2026 — owe no federal tax at all. This is a genuinely useful planning tool for lower-income years: retirees living on modest withdrawals, someone between jobs, or anyone with a year of unusually low ordinary income may be able to realize substantial long-term gains completely tax-free by staying under that threshold.
The extra tax high earners should know about
Above $200,000 (single) or $250,000 (married filing jointly) in total income, an additional 3.8% Net Investment Income Tax can apply on top of the regular capital gains tax. This calculator estimates it using your total income and gains; the real calculation (Form 8960) uses a slightly broader definition of investment income and modified AGI, so treat this as a close estimate rather than an exact figure if you’re near the threshold.
Using this calculator
Enter your ordinary taxable income — after deductions, not your gross salary — since that’s what gains actually stack on top of. If you’re deciding whether to wait for a sale to cross the one-year holding mark, compare the short-term and long-term tax figures above on the same gain amount to see exactly what patience is worth in your specific situation.
This article is for educational purposes only and isn't legal, financial, or tax advice. See our Disclaimer for details.
