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 Social Security Taxes Estimate how much of your Social Security benefit may be considered taxable. Tax Rules When Selling Your Home The tax rules governing profits you realize from the sale of your home have changed in recent years. Comparing Investments This calculator compares the net gain of a taxable investment versus a tax-favored one.