Estate tax returns are due fast. IRC 6075(a) requires Form 706 within nine months after the date of death. In those nine months, the executor has to be appointed, find every asset, get date-of-death values, obtain appraisals for real estate and closely held businesses, gather the decedent's lifetime gift history, and figure out deductions. Families are also grieving, which slows everything.
The good news is that getting more time to file is easy if you ask on time. The bad news is that more time to file is not more time to pay, and the deadlines around the return keep moving even when the return does not.
Who has to file
A Form 706 is required when the gross estate plus adjusted taxable gifts exceeds the basic exclusion amount. For decedents dying in 2026, that amount is $15,000,000 under Rev. Proc. 2025-32, as set by the One Big Beautiful Bill Act. Estates below that threshold may still choose to file to elect portability of the deceased spouse's unused exclusion. That choice has its own timing rules, discussed in the guide to portability and the late DSUE election.
Florida does not have an estate tax return. Everything on this page is federal. See Florida has no estate tax; the IRS still does.
The nine-month deadline
The due date is nine months after death, on the same day of the month. Someone who died on March 10, 2026, has a Form 706 due December 10, 2026. If that date falls on a weekend or legal holiday, the next business day applies.
The estate tax is also due nine months after death. Interest under IRC 6601 runs from that date on any unpaid tax, whether or not the return is extended.
The automatic six-month extension
Treas. Reg. 20.6081-1(b) gives every estate an automatic six-month extension to file Form 706 if Form 4768, Application for Extension of Time To File a Return and/or Pay U.S. Estate (and Generation-Skipping Transfer) Taxes, is filed on or before the original due date. No explanation is required for the automatic extension.
The regulation does require Form 4768 to include an estimate of the estate and GST tax. Do not leave that blank. The estimate is also the number that drives how much you should pay with the extension to avoid late payment penalties.
If the estate misses the original due date without filing Form 4768, all is not lost, but it gets harder. Treas. Reg. 20.6081-1(c) allows the IRS, in its discretion, to grant an extension for good and sufficient cause, including to an estate that did not request the automatic extension. The request must explain why a reasonably complete return could not be filed and why the automatic extension was not requested. Except for an executor who is abroad, the total extension cannot exceed six months beyond the original due date.
Extension to file is not extension to pay
Treas. Reg. 20.6081-1(e) says it plainly: an extension of time for filing a return does not operate to extend the time for payment of the tax. If you extend the return but not the payment, interest is due from the original date and the estate is subject to late payment penalties.
Executors get caught here constantly. The CPA files Form 4768, the family relaxes for six months, and the return shows a large balance that has been accruing the failure-to-pay penalty under IRC 6651(a)(2) since the original due date.
The fix is to pay a good-faith estimate by the nine-month date. If the estate genuinely cannot pay because its assets are illiquid, request an extension of time to pay in Part III of Form 4768. That is a separate request under IRC 6161, and it is not automatic. See extensions of time to pay estate tax under section 6161. Estates built around a closely held business may qualify for installment payments under section 6166 instead.
What a complete return means
Treas. Reg. 20.6081-1(d) requires a return as complete as possible before the extension expires. That return becomes the return of record. It cannot be amended after the extension period, although supplemental information can be filed later that may change the finally determined tax.
Practically, that means you should not file a skeleton return to beat the deadline and plan to fix it later. Missing appraisals and unexplained valuation positions are what turn a routine filing into an estate tax audit.
The Form 8971 deadline that follows the 706
IRC 6035 requires the executor of an estate required to file Form 706 to furnish a statement to the IRS and to each beneficiary identifying the value of property they received, as reported on the return. That statement is Form 8971 with its Schedule A.
The deadline is the earlier of 30 days after the Form 706 due date, including extensions, or 30 days after the Form 706 is actually filed. If the return is filed early, the 8971 clock starts early.
If values change later, such as after an audit, IRC 6035(a)(3)(B) requires a supplemental statement within 30 days after the adjustment. The point of the rule is basis consistency: beneficiaries cannot claim a higher basis for income tax purposes than the value reported for estate tax.
Under the regulations, estates that file Form 706 only to elect portability, and are not otherwise required to file, generally do not need to file Form 8971.
Getting ready inside nine months
The fastest way to need an extension is to start the appraisals late. A practical sequence for a Sarasota estate:
- Order date-of-death values from every bank and brokerage in the first month.
- Engage qualified appraisers for real estate and any business interests right away. Waterfront and commercial property can take longer.
- Request the decedent's prior gift tax returns and gift history, since adjusted taxable gifts change the computation.
- Identify debts, mortgages and expected administration expenses for the deduction schedules.
- At month six or seven, decide whether the return will be ready. If not, prepare Form 4768 with a realistic tax estimate and a payment.
Penalties if you miss
A late Form 706 without an extension triggers the failure-to-file penalty under IRC 6651(a)(1): 5 percent of the unpaid tax per month, up to 25 percent. Late payment adds 0.5 percent per month under IRC 6651(a)(2). Both can be abated for reasonable cause, but the standard is strict, and under IRM 20.1.1.3.3.2.1, first time abatement does not apply to Form 706. When both penalties run in the same month, IRC 6651(c)(1) reduces the failure-to-file penalty by the failure-to-pay penalty for that month, so the combined rate is 5 percent, not 5.5. See estate tax penalties and reasonable cause.
A working calendar
| Item | Deadline |
|---|---|
| Form 706 and estate tax payment | 9 months after death |
| Form 4768 for automatic extension | On or before the 9-month date |
| Extended Form 706 | 15 months after death |
| Form 8971 and Schedules A | Earlier of 30 days after the due date (with extensions) or 30 days after filing |
| Supplemental Form 8971 | 30 days after a value adjustment |
Remember that Form 706 also reports generation-skipping transfer tax on direct skips occurring at death, and Treas. Reg. 20.6081-1(a) requires the Form 4768 estimate to cover both the estate tax and the GST tax.
Put those dates on the calendar the week you are appointed. Then work backward to the appraisals.
Interest is not a penalty and is not abated for reasonable cause. It is charged at the federal underpayment rate, which the IRS sets quarterly under IRC 6621, and it compounds daily under IRC 6622. On a large estate tax balance, a few months of interest is real money, which is one more reason to pay a good-faith estimate on time.
If the nine-month date is closing in and the return is not close to ready, call (813) 229-7100. Let's talk.
Frequently asked questions
When is Form 706 due?
Nine months after the date of death under IRC 6075(a). For someone who died on March 10, 2026, the return is due December 10, 2026. The tax is due on the same date.
How do I get an extension to file Form 706?
File Form 4768 on or before the original due date. Under Treas. Reg. 20.6081-1(b), that gives an automatic six-month extension. The form must include an estimate of the estate and generation-skipping transfer tax.
Does Form 4768 extend the time to pay estate tax?
Not automatically. Treas. Reg. 20.6081-1(e) says an extension to file does not extend time to pay. A separate request for extension of time to pay under IRC 6161 is made in Part III of Form 4768 and requires a showing of reasonable cause or undue hardship.
What is Form 8971 and when is it due?
Form 8971 reports the estate tax values of property to the IRS and to beneficiaries under IRC 6035, so their basis is consistent with the estate tax return. It is due no later than 30 days after the Form 706 due date (including extensions) or 30 days after the Form 706 is filed, whichever is earlier.