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 Red Flags for Tax Auditors Here are six flags that may make your tax return prime for an IRS audit. Qualifying For Medicare Under Age 65 You might qualify for Medicare if you’re under 65-years-old. This article will explain the conditions where you may qualify for Medicare early. Lifetime of Earnings Estimate how much you have the potential to earn during your working years.