The Facts About Income Tax Millions faithfully file their 1040 forms each April. But some things about federal income taxes may surprise you. Share | Related Content Capital Gains Tax Estimator Use this calculator to estimate your capital gains tax. Do You Owe The AMT? If you want to avoid potential surprises at tax time, it may make sense to know where you stand when it comes to the AMT. Home Mortgage Deduction Use this calculator to assess the potential benefits of a home mortgage deduction.