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 Home Mortgage Deduction Use this calculator to assess the potential benefits of a home mortgage deduction. You May Need to Make Estimated Tax Payments If… Have income that isn’t subject to tax withholding? Or insufficient withholdings? You may have to pay estimated taxes. Tax Freedom Day Assess how many days you'll work to pay your federal tax liability.