How the marital deduction and DSUE calculator works
Under IRC 2056 the United States allows an unlimited marital deduction: property passing outright to a surviving U.S. citizen spouse, or into a qualifying QTIP trust, leaves the taxable estate entirely. That is a structural difference from systems that cap the spousal deduction at a fixed ceiling — here there is no ceiling, so a full spousal bequest can reduce the taxable estate to zero.
Whatever is left of the decedent's basic exclusion amount need not be wasted. The executor may elect portability on a timely filed Form 706, transferring the deceased spousal unused exclusion (DSUE) to the survivor, who can then shelter both amounts. The election is available only if Form 706 is actually filed, even when no tax would otherwise be due.
The top estate tax rate and the basic exclusion amount are shown on a 2026 basis, and the exclusion is entered as an editable field because it is indexed annually and has been changed by statute more than once. Confirm the current figure in the IRS instructions to Form 706. A surviving spouse who is not a U.S. citizen generally does not qualify for the unlimited deduction unless the property passes to a QDOT under IRC 2056A.
This tool is a planning estimate only. An actual liability depends on state estate or inheritance tax, prior gifts, valuation discounts, deductions for debts and administration expenses, and charitable bequests. Review your situation with an estate attorney or CPA.
Frequently asked questions
Yes, if you want portability. The DSUE amount is preserved only when the executor files a timely Form 706 and makes the portability election for the surviving spouse.
It defers it. The marital deduction removes the transfer from the first estate, but the same assets are then included in the surviving spouse's estate, which is why portability and credit shelter planning matter.