What's My Potential Estate Tax? This calculator helps estimate your federal estate tax liability. You are viewing this website at a small screen resolution which doesn't support calculators. Click here to view this calculator. Share | Related Content When Do You Need a Will? When do you need a will? The answer is easy: Right Now. Understanding the Alternate Valuation Date Executors can value the estate on the date of death, or on its six-month anniversary —the “Alternate Valuation Date." Principles of Preserving Wealth How federal estate taxes work, plus estate management documents and tactics.