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. A Brief History of Estate Taxes Federal estate taxes have long since been a lucrative source of funding for the federal government. Principles of Preserving Wealth How federal estate taxes work, plus estate management documents and tactics.