How much capital gains tax will I pay on $300,000?

How Much Capital Gains Tax Will You Pay on $300,000?

If you're selling an asset—like stocks, real estate, or a business—and realize a $300,000 long-term capital gain, how much tax you’ll owe depends on your filing status and overall taxable income. For the 2025 tax year (due April 2026), the federal long-term capital gains rates are tiered based on income.

Assuming you're married and filing separately, the brackets are as follows: income up to $48,350 in long-term gains is taxed at 0%. Gains between $48,350 and $300,000 are taxed at 15%, and anything above $300,000 jumps to 20%. Since your gain is exactly $300,000, the first chunk falls into the 0% bracket, the bulk into 15%, and none into the 20% tier—at least for this filing status.

Here’s the breakdown: $48,350 of your gain would be tax-free. The remaining $251,650—falling between $48,350 and $300,000—would be taxed at 15%. That results in a federal capital gains tax of $37,747.50. Keep in mind, this doesn’t include potential state taxes, which vary widely. States like California or New Jersey add their own capital gains rates, while others like Texas or Florida have no state income tax at all.

Also, remember this applies only to long-term gains—assets held for more than a year. Short-term gains are taxed as ordinary income, often at a much higher rate.

Your actual tax outcome could shift depending on your total income, deductions, and state of residence. If you're close to a threshold, strategic planning—like timing the sale or using tax-advantaged accounts—could help reduce your burden. Always consult a tax professional to tailor a strategy to your situation.