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. Four Steps to Valuing an Estate Determining the value of your estate, or for someone who has passed away, can be a complex undertaking. Principles of Preserving Wealth How federal estate taxes work, plus estate management documents and tactics.