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 | Related Content The Facts About Income Tax Millions faithfully file their 1040 forms each April. But some things about federal income taxes may surprise you. Tax Rules When Selling Your Home The tax rules governing profits you realize from the sale of your home have changed in recent years. Tax Freedom Day Assess how many days you'll work to pay your federal tax liability.