The Facts About Income Tax Millions faithfully file their 1040 forms each April. But some things about federal income taxes may surprise you. Have A Question About This Topic? Name Email Address Message Thank you! Oops! Related Content Capital Gains Tax Estimator Use this calculator to estimate your capital gains tax. Social Security Taxes Estimate how much of your Social Security benefit may be considered taxable. Should You Tap Retirement Savings to Fund College? There are three things to consider before dipping into retirement savings to pay for college.