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 Question Thank you! Oops! Related Contents Federal Income Tax Use this calculator to estimate your income tax liability along with average and marginal tax rates. What Do Your Taxes Pay For? Here's a breakdown of how the federal government spends your tax money. Social Security Taxes Estimate how much of your Social Security benefit may be considered taxable.