
Chapter 01
The tax and the exemption
How the federal estate tax is calculated, portability for married couples and the marital deduction.
How the federal estate tax works
The calculation follows a fixed sequence:
- Gross estate — everything owned or controlled at death, including life insurance the decedent owned, retirement accounts and the decedent’s share of community property.
- Deductions — debts, expenses, property passing to a U.S. citizen spouse (the unlimited marital deduction) and to charity.
- Taxable estate — plus adjusted taxable gifts made during life.
- Exemption — the basic exclusion amount, $15 million per person in 2026, plus any unused exemption received from a deceased spouse.
- Tax — up to 40% on the amount above the exemption, with the return (Form 706) due nine months after death.
Portability for married couples
When the first spouse dies, the unused part of that spouse’s exemption — the deceased spousal unused exclusion amount — can pass to the survivor, but only if the executor files a timely estate tax return electing portability, even when no tax is due. The IRS allows a simplified late election within five years after death for estates that were not otherwise required to file (Revenue Procedure 2022-32). Portability does not carry over the generation-skipping transfer tax exemption, and the amount carried over is not indexed for inflation.
The marital deduction and non-citizen spouses
Property passing to a surviving spouse who is a U.S. citizen qualifies for an unlimited marital deduction, deferring tax until the survivor’s death. If the surviving spouse is not a U.S. citizen, the marital deduction is generally available only through a qualified domestic trust, or QDOT (Internal Revenue Code §2056A). Trusts that qualify for the deduction, such as QTIP trusts, let the first spouse to die decide who ultimately receives the property.

