The Short Answer
Every person can pass a certain amount of wealth free of federal estate tax. In 2026 that amount is $15 million each. When the first spouse in a marriage dies and does not use all of theirs, the leftover, called the deceased spousal unused exclusion, can be transferred to the surviving spouse. That spouse then has their own $15 million plus whatever they inherited, up to roughly $30 million of shelter. Lawyers call this portability, and the whole point of this page is simple: it does not happen automatically, and missing it can cost your family a great deal.
Why So Many Families Lose It
Here is how the money slips away. After a spouse dies with a modest estate, no one files a federal estate-tax return, because nothing is owed. That feels right, and it is the mistake. Claiming the unused exemption requires the executor to file Form 706, the federal estate-tax return, and check the box electing portability, even when the estate is small and tax-free. The only reason to file may be to lock in that exemption for the future. No one sends the grieving spouse a reminder, so the return never gets filed, and a second $15 million of protection disappears for good.
The Deadline, and the Safety Net
The normal deadline is 9 months after the date of death, with a 6-month extension available on request. If you have just lost a spouse, that is the window to act in. But if you are reading this years later and realize it was never done, do not give up: when the estate was not otherwise required to file, the IRS allows a simplified late election up to the fifth anniversary of the death. Many surviving spouses still have time to fix this, as long as they move before that five-year door closes.
"But the Exemption Is $15 Million, So Why Bother?"
It is a fair question, and the honest answer is about protecting against what you cannot predict:
- Estates grow. A surviving spouse who is comfortably under $15 million today can cross it over a long retirement through investments, a business, or appreciating real estate.
- The law changes. The exemption is set by Congress; before the current law it was scheduled to drop to roughly half this size, and a future Congress could lower it again. If it drops again, the exemption you preserved becomes far more valuable.
- It is cheap insurance. Filing for portability costs a fraction of the tax it can save, and the election can never be made after the window closes.
For a surviving spouse with meaningful assets, the question is usually not whether to file, but how quickly.
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Book a free 30-minute consult. We will tell you whether a portability filing is worth it for your family, and handle it remotely if it is.
Book your free consultTwo Traps Worth Knowing
- The remarriage trap. A surviving spouse can only use the unused exemption of their most recent deceased spouse. Inherit a DSUE, remarry, and lose that new spouse, and the first spouse’s amount can vanish. Order and timing matter.
- The grandchildren gap. Portability covers the estate and gift tax exemption, but the separate generation-skipping exemption is not portable. Families who want to benefit grandchildren usually need a trust for that piece, not portability alone.
How We Help, and Florida’s Advantage
Florida has no state estate tax of its own, so a Florida family only has the federal tax to plan around, which makes portability one of the simplest protective moves available. (Still tied to a state that does tax estates? See what it would take versus Florida.) We prepare portability-only Form 706 returns for surviving spouses, walk you through whether it is worth doing in your situation, and coordinate it with the rest of the plan, including a revocable trust or, for married couples with highly appreciated assets, a community property trust. Because this is custom work, we quote it at the consult.
Frequently Asked Questions
What Is Estate Tax Portability?
Portability lets a surviving spouse keep their late spouse’s unused federal estate-tax exemption instead of losing it. Each person can pass a certain amount (in 2026, $15 million) free of federal estate tax. When the first spouse dies without using all of theirs, the leftover amount, called the DSUE, can be moved to the survivor, who then has their own exemption plus the inherited one, up to roughly $30 million. The catch is that it does not happen on its own; someone has to claim it.
How Do You Actually Claim Portability?
The executor has to file a federal estate-tax return, Form 706, for the spouse who died, and check the box electing portability. This is true even when the estate is small and owes no tax at all; the only reason for filing may be to preserve the exemption. No filing, no portability. This is the step that quietly costs families a fortune, because no one tells the surviving spouse it needs to be done.
What’s the Deadline to Elect Portability?
The normal deadline is 9 months after the date of death, with an automatic 6-month extension available. But there is a safety net: if the estate was not otherwise required to file a return, the IRS allows a simplified late election (under Rev. Proc. 2022-32) up to the fifth anniversary of the death. So a widow or widower who finds out years later often still has time, if they act before that five-year window closes.
Why Would I Bother if the Exemption Is Already $15 Million?
A few good reasons. The surviving spouse’s own estate can grow well past $15 million over the years through investments, a business, or real estate. The exemption is also a creature of federal law that Congress can lower; before 2026 it was set to fall to roughly half this amount, and Congress could lower it again. And the GST (generation-skipping) side has its own rules. Filing for portability when the first spouse dies is inexpensive insurance that keeps a second $15 million of shelter available, just in case. Letting it lapse is a decision you cannot undo.
Does Florida Have an Estate Tax?
No. Florida has no state estate tax and no inheritance tax, so this is entirely about the federal estate tax. That is actually good news: a Florida family only has the one tax to plan around, and portability is one of the simplest, cheapest moves to protect against it.
What if the Surviving Spouse Remarries?
There is an important trap here. A surviving spouse can only use the unused exemption of their most recent deceased spouse. If you inherit a DSUE, remarry, and your new spouse also dies, the first spouse’s unused amount can be lost. The timing and order of using it matter, which is exactly the kind of thing worth a short conversation rather than a guess.
Is the Generation-Skipping (GST) Exemption Portable Too?
No. Portability applies to the estate and gift tax exemption, but the separate generation-skipping transfer tax exemption is not portable. For families who want to benefit grandchildren, that gap needs its own planning, often a trust, rather than relying on portability alone.
Should I File Even Though It Costs Money and Effort?
For most surviving spouses with meaningful assets, yes, or at least it deserves a real look. The cost of preparing a portability-only Form 706 is small next to the potential tax it can save the next generation, and the election cannot be made after the window closes. We will tell you honestly whether your situation makes filing worthwhile or whether you can safely skip it.
Common Situations
The widow who almost lost millions. A woman’s husband dies with a $4 million estate, all passing to her tax-free. No one mentions portability, and no return is filed. Three years later her own assets have grown and the exemption is rumored to be dropping. Because the five-year window is still open, we file a late portability election and preserve his unused $15 million for her family.
The adult child handling it. A son settling his father’s small Florida estate assumes that, with no tax owed, there is nothing to file. We flag the portability election so his mother keeps the option open, a quiet move that could save the next generation a large tax bill.
The couple planning ahead. A married couple with a growing estate builds portability into the plan in advance, so that whoever survives knows exactly what to file and when, instead of discovering it too late.
Sources of Law
- IRC §2010(c): the applicable exclusion amount and the deceased spousal unused exclusion (portability). 2026 exemption: $15,000,000 per person (One Big Beautiful Bill Act). (retrieved 2026-06-07)
- IRS Form 706 and instructions: portability is elected on a timely filed estate-tax return. Standard due date is 9 months after death (Form 4768 extension available).
- Rev. Proc. 2022-32: simplified method to make a late portability election within 5 years of death for estates not otherwise required to file.
- The generation-skipping transfer (GST) exemption (IRC §2631) is not portable. Florida imposes no state estate or inheritance tax.
Updated on June 10, 2026. Reviewed by Kevin D. Klagge, Esq., Fla. Bar No. 99502. General information about federal tax and Florida law, not legal or tax advice, and no attorney-client relationship is created. Exemption figures are 2026 and set by federal law that may change; nothing here guarantees a tax result. Do not send confidential information until we have agreed to represent you.