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. When Heirs are Imperfect The money problems or bad lifestyle habits of adult children could lead to the squandering of any inheritance they receive. What Is My Life Expectancy? Estimate how many years you may need retirement assets or how long to provide income to a surviving spouse or children.