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 Federal Income Tax Use this calculator to estimate your income tax liability along with average and marginal tax rates. Does Your Child Need to File an Income Tax Return? When your child has income, there’s a good chance that he or she will need to report it and pay taxes. Tax Management Strategies Learn more about taxes, tax-favored investing, and tax strategies.