About the Capital Gains Tax Calculator
Most capital-gains calculators ask one question and multiply by 15%. The real computation has a shape: long-term gains stack on top of your ordinary taxable income and get sliced across the 0%, 15% and 20% bands they actually occupy — so the identical $40,000 gain can owe $0 or $9,520 depending on your wages. This tool draws the slices instead of hiding them.
The numbers are the real 2026 ones, verified at source: the Rev. Proc. 2025-32 thresholds, the never-indexed $200k/$250k NIIT lines, and short-term gains priced through the same Node-validated 2026 bracket engine as our paycheck calculator — including the property, checked across two thousand random cases, that long-term never taxes more than short-term.
The rule: a loss is disallowed if you buy the same (or substantially identical) security within 30 days BEFORE or AFTER the sale — a 61-day window. It applies across your accounts, IRAs included. Gains have no wash-sale rule, which is what makes 0%-band harvesting legal and boring.
How to Use the Capital Gains Tax Calculator
Enter the gain, whether you held past one year, your ordinary income and filing status. The result is the federal tax on that gain, drawn honestly: the slice bar shows how much lands in the 0%, 15% and 20% bands given where your income leaves off, and the NIIT line appears only when your modified AGI actually crosses its threshold.
The One-Year Line Is Worth Real Money
Hold an asset one year or less and the gain is ordinary income — up to 37% federal. One day past a year and the 0/15/20 schedule applies. The timing panel prices your specific position both ways and names the calendar date it turns long-term, because “wait five more weeks, save $4,300” is a decision, not trivia. (Holding period runs from the day after purchase through the sale date.)
What This Calculator Deliberately Leaves Out
State income tax on gains (most states tax them as ordinary income — your state’s rate is in our Paycheck Calculator’s tables), depreciation recapture on rentals (25% rate, its own maths), collectibles (28%), qualified small-business stock, and loss netting across your whole portfolio. Each is real; pretending one calculator handles them all is how tools lie. For a home sale specifically, start with the Home Sale Proceeds Calculator and its §121 exclusion check — most home gains never reach this page.
Related tools: the DCA Backtest for how the gain got here, the Roth IRA Calculator for the account where none of this applies, and the FIRE Calculator for the plan the 0% band quietly powers. Browse every Personal Finance tool for more.
Federal estimates for planning, not tax advice. 2026 figures verified at source (Rev. Proc. 2025-32; NIIT thresholds statutory). Assumes the standard deduction, no other investment income, and MAGI ≈ income + gain. Netting rules, AMT edge cases and state tax are yours to layer on — or your CPA’s.
Frequently Asked Questions
What are the 2026 long-term capital gains brackets?
From IRS Revenue Procedure 2025-32 (verified at source): the 0% rate applies up to $49,450 of taxable income for single filers ($98,900 married filing jointly, $66,200 head of household); 15% up to $545,500 ($613,700 MFJ); 20% above. These thresholds are TAXABLE-income levels — after the standard deduction — and the gain fills whatever room your ordinary income leaves, which is the part most calculators skip.
How does the "stacking" actually work?
Long-term gains sit on top of your ordinary taxable income like water filling a glass. Ordinary income fills the bands first; the gain occupies the space above it. Example: $40,000 of wages leaves you about $23,900 of taxable ordinary income (2026 single, standard deduction) — so the first $25,550 of a long-term gain fits under the $49,450 line at 0%, and only the rest pays 15%. Same gain, different wages, completely different tax — which is why this calculator asks for your income instead of pretending the gain lives alone.
What is the NIIT?
The 3.8% Net Investment Income Tax, on top of capital-gains rates, for higher earners: it applies to the smaller of your net investment income or the amount your modified AGI exceeds $200,000 (single/HoH) or $250,000 (MFJ) — thresholds set by statute in 2013 and never indexed, so inflation drags more people in every year. At the top, LTCG + NIIT = 23.8% federal.
How much does waiting for long-term status save?
A short-term gain is taxed at your ordinary marginal rate — up to 37% — while the same gain held past one year pays 0/15/20%. For someone in the 24% bracket with a $50,000 gain, selling a month early can cost roughly $4,500. The holding period is measured from the day after purchase to the sale date, and the subscriber panel computes your exact tax both ways with the calendar date the position turns long-term.
What is tax-gain harvesting?
The 0% band's legal gift: if your taxable income leaves room under the 0% threshold, you can sell appreciated assets, realise that much gain federally tax-free, and immediately rebuy — resetting your basis higher. (The wash-sale rule only restricts realising LOSSES, not gains.) A retiree couple with $60,000 of taxable income has roughly $38,900 of 0% headroom in 2026. The subscriber panel computes yours.
