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 Making Your Tax Bracket Work Have you explored all your options when it comes to managing your taxable income? Tax Reform: Before and After What did the 2017 Tax Cuts and Jobs Act change? Here's a quick snapshot. Federal Income Tax Use this calculator to estimate your income tax liability along with average and marginal tax rates.