Tax Freedom Day Assess how many days you'll work to pay your federal tax liability. 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 Retiring Wild: National Parks and You Get ready to enjoy America’s national park system with this helpful article. Federal Income Tax Use this calculator to estimate your income tax liability along with average and marginal tax rates. Red Flags for Tax Auditors Here are six flags that may make your tax return prime for an IRS audit.