A deceased spouse’s unused exemption doesn’t automatically transfer — it requires an affirmative election, and skipping that election can waste millions of dollars of exemption permanently.
How it works
The DSUE amount is whatever’s left of the deceased spouse’s exclusion after their own taxable estate uses some of it. That DSUE, once elected via a timely Form 706, adds directly to the surviving spouse’s own exclusion.
What this does not include
This doesn’t check the Form 706 filing deadline (generally 9 months from death, or 15 with a timely extension) — missing that deadline forfeits the portability election even if the estate would otherwise have qualified.
How to use this calculator
- Enter the current exclusion amount, the deceased spouse’s taxable estate, and the surviving spouse’s own exclusion.
Frequently asked questions
Is portability automatic?
No — the executor must affirmatively elect it by filing a timely and complete Form 706, even for an estate that wouldn’t otherwise be required to file one.
What happens if a couple divorces after electing portability?
DSUE from a former spouse is generally not available if the surviving spouse remarries and that new spouse also predeceases them — DSUE rules only allow using the most recently deceased spouse’s unused exclusion.
Does DSUE also cover the GST exemption?
No — the GST exemption is not portable between spouses, unlike the basic estate/gift tax exclusion; this site’s separate GST calculator addresses that exemption on its own terms.
