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 Home Mortgage Deduction Use this calculator to assess the potential benefits of a home mortgage deduction. Six Most Overlooked Tax Deductions Six overlooked tax deductions to help manage your tax bill. Comparing Investments This calculator compares the net gain of a taxable investment versus a tax-favored one.