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 | Free Retirement Guide It's never too soon to start preparing for retirement. But do you know what to look out for? Download our free ebook, "Retire Happy: A Simple Guide to Your Next Big Adventure." 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. Comparing Investments This calculator compares the net gain of a taxable investment versus a tax-favored one.