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! Test Your Investment Knowledge! How much do you know about investing? Take our quiz and find out instantly. First Name Last Name Email Address Thank you! Oops! 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. Red Flags for Tax Auditors Here are six flags that may make your tax return prime for an IRS audit. Social Security Taxes Estimate how much of your Social Security benefit may be considered taxable.