Capital Gains Tax Calculator

The One-Year Rule: Short-Term vs. Long-Term

The most important factor in capital gains taxation is the holding period. If you sell an asset you have owned for one year or less, the profit is a short-term capital gain and is taxed as ordinary income. Depending on your tax bracket, that means you could pay up to 37% on the gain.

If you hold the asset for more than one year (1 year and 1 day), the profit becomes a long-term capital gain. Long-term gains are taxed at preferential rates: 0%, 15%, or 20%. For most investors, the difference between selling a stock at 11 months versus 13 months can be tens of thousands of dollars in taxes.

How Long-Term Capital Gains Brackets Work

Unlike ordinary income tax brackets, which apply to your total income, long-term capital gains "stack" on top of your ordinary income. This means the 0%, 15%, or 20% rate is applied based on where the gain falls in relation to your total taxable income.

For example, if you are single and have $40,000 of ordinary income, you are in the 12% ordinary tax bracket. The 0% long-term capital gains bracket goes up to $47,025. If you realize a $7,000 long-term gain, it all falls into the 0% bracket, and you owe $0 in federal tax on it. But if you realize a $20,000 gain, the first $7,025 is taxed at 0%, and the remaining $12,975 is taxed at 15%.

The Net Investment Income Tax (NIIT)

High earners face an additional surtax on investment income. The Net Investment Income Tax (NIIT) is a 3.8% tax on the lesser of your net investment income (which includes capital gains, dividends, and interest) or the amount by which your modified adjusted gross income exceeds $200,000 (single) or $250,000 (married filing jointly).

This means that if you are a high earner, your long-term capital gains rate could effectively be 18.8% or 23.8%, rather than 15% or 20%. The NIIT is designed to help fund Medicare and is calculated on Form 8960.

Strategies to Minimize Capital Gains Tax

Tax-Loss Harvesting: You can use capital losses to offset capital gains. If you have $10,000 in gains and $4,000 in losses, you only pay tax on $6,000. If your losses exceed your gains, you can deduct up to $3,000 per year against ordinary income and carry the rest forward.

Holding Period Management: Do not sell an asset just before the one-year mark if you can wait a few weeks. The difference between short-term and long-term rates is substantial.

Section 121 Exclusion: If you are selling your primary residence, you can exclude up to $250,000 (single) or $500,000 (married) of capital gain, provided you have lived in the home for two of the last five years.

Do State Taxes Apply to Capital Gains?

In most states, capital gains are taxed as ordinary income, with no preferential long-term rate. If you live in California, your capital gains could be taxed at up to 13.3%. New York has its own brackets, and states like Washington have a specific excise tax on certain long-term gains.

Nine states have no income tax at all: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming. For high-net-worth investors, the state of residence can significantly impact the after-tax return on an investment.