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? Address Thank you! Oops! Related Contents Comparing Investments This calculator compares the net gain of a taxable investment versus a tax-favored one. Does Your Child Need to File an Income Tax Return? When your child has income, there’s a good chance that he or she will need to report it and pay taxes. Social Security Taxes Estimate how much of your Social Security benefit may be considered taxable.