Federal Income Tax Use this calculator to estimate your income tax liability along with average and marginal tax rates. You are viewing this website at a small screen resolution which doesn't support calculators. Click here to view this calculator. Have A Question About This Topic? Name Email Address Message Thank you! Oops! Related Content How Income Taxes Work A quick look at how federal income taxes work. Buying vs. Leasing a Car Whatever your relationship with your car, it may eventually come time for a new one. Familiarize yourself with your options. Important Birthdays Over 50 Here's a look at several birthdays and “half-birthdays” that have implications regarding your retirement income.