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 What's My Potential Estate Tax? This calculator helps estimate your federal estate tax liability. Long-Term-Care Needs Determine your potential long-term care needs and how long your current assets might last. Red Flags for Tax Auditors Here are six flags that may make your tax return prime for an IRS audit.