Capital Gains Tax Estimator Use this calculator to estimate your capital gains tax. You are viewing this website at a small screen resolution which doesn't support calculators. Click here to view this calculator. Share | Have A Question About This Topic? Name Email Address Message Thank you! Oops! Related Content Tax Freedom Day Assess how many days you'll work to pay your federal tax liability. How Income Taxes Work A quick look at how federal income taxes work. Social Security Taxes Estimate how much of your Social Security benefit may be considered taxable.