What line on my Form 2024 IRS1040 is the income used in determining my long term capital gain tax bracket?

[MinhT1]

The long term capital gain tax rates are based on your taxable income on line 15 of form 1040.

Long term capital gains are taxed at 0% if your taxable income is less than $47,025 for Single or MFS or less than $94,050 for MFJ..

However, long term capital gains are included in your taxable income for the calculation of these thresholds, and that part of long term gains which crosses over $47,025 (Single or MFS) or $94,050 (MFJ) is taxed at 15%. For taxable incomes over $518,900 (Single); $291,850 (MFS) or $583,750 (MFJ). The long-term capital gain tax rate is 20%.

Please read this IRS document for more information.