Capital Gains Tax Calculator

What Is the Capital Gains Tax Calculator?

How long you hold an investment before selling it significantly changes how the resulting gain is taxed. Gains on assets held one year or less (short-term) are taxed as ordinary income at your regular marginal rate -- the same bracket structure as wages. Gains on assets held longer than one year (long-term) qualify for separate, generally lower preferential rates instead. This is a genuinely different tax regime from ordinary income tax, not just a different rate applied to the same formula.

How to Use This Calculator

Enter your capital gain amount, select short-term or long-term holding period, your ordinary marginal tax rate (for short-term gains), and the long-term capital gains rate that applies to your income level (commonly 0%, 15%, or 20% depending on total taxable income).

The Formula

Worked Example

The identical gain results in $900 less tax simply by qualifying for long-term treatment -- a real incentive to hold investments beyond the one-year mark when practical.

Practical Uses

Use this before selling an investment near the one-year holding mark to see the real tax difference between selling now (short-term) versus waiting (long-term).

From Sale to Gain: What to Enter

The calculator asks for the gain, so you first need to compute it. A gain is the sale price minus your cost basis, which is generally what you paid plus purchase costs, and less selling costs. As a hypothetical example, you buy shares for $8,000, sell them for $11,500, and pay $50 in fees. The gain is $3,450. Entering that with a 24% ordinary rate for a short-term sale gives $828, while a 15% long-term rate gives $517.50. The difference is $310.50 for holding past the one-year line.

Adjustments That Change the Inputs

• Reinvested dividends and adjustments to basis. Automatically reinvested dividends usually increase your basis, and forgetting this can overstate your gain.
• Losses. Capital losses generally offset capital gains, and rules exist for how excess losses can be used. A net loss for the year may reduce tax rather than create it.
• Multiple lots. If you sold shares bought on different dates, each lot may have its own holding period, so short-term and long-term portions should be calculated separately.
• Inherited or gifted assets. Basis and holding period rules for these can differ, so check the official guidance.

Limits of This Calculator

The tool applies a single rate to the gain you enter. Actual tax can be affected by how your gain stacks on top of your other income, which decides where it falls in the long-term rate tiers. Additional taxes, such as the net investment income tax at higher income levels, state income tax on gains, and special rates for collectibles or certain real estate depreciation, are not included. Retirement accounts like IRAs and 401(k)s follow different rules, since gains inside them are generally not taxed as capital gains when sold within the account.

Using It for Timing Decisions

If a sale is close to the one-year mark, compare the two outcomes before selling, but do not let tax alone drive the decision. A price drop while waiting can easily outweigh the tax saved. For large or complex sales, such as business interests or property, talk with a tax professional and confirm rates and thresholds on IRS.gov.

Frequently Asked Questions