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 Question Thank you! Oops! Related Content The Pre-Retirement Checklist This checklist can give you a quick snapshot of how prepared you are. A Brief History of Estate Taxes Federal estate taxes have long since been a lucrative source of funding for the federal government. Tax Freedom Day Assess how many days you'll work to pay your federal tax liability.