The important date depends on when the person died and what state they lived in
The federal estate tax return, called Form 706, is due nine months after the person's death. If the person died on March 15, the return is due December 15 of the same year. If you need more time, you can request a six-month extension, which moves the important date to fifteen months after death.
State estate tax returns have different important date depending on which state the person lived in. Some states follow the federal nine-month rule. Others give you less time — Connecticut, for example, requires its return within four months. A few states give you more time. You need to check the rules for the state where the person lived, not where their property is located.
The person handling the estate — called the executor or personal representative — is responsible for filing on time. If no return is filed by the important date and no extension was requested, the IRS can impose penalties and interest on any taxes owed.
Key Takeaways
- Federal Form 706 is due nine months after death, with a possible six-month extension available.
- State important date vary widely, from four months to nine months or longer, depending on where the person lived.
- The executor must file even if no tax is owed, if the estate is large enough to require a return.
- Missing the important date without an extension triggers IRS penalties and interest on any unpaid tax.
- An extension request must be filed before the original important date, not after.
Whether a return must be filed at all
Not every estate needs to file Form 706. The IRS only requires a return if the estate's total value is above a certain threshold. That threshold changes each year. In 2024, for example, an estate must file only if it exceeds $13.61 million. In 2025, the threshold is $13.99 million. These numbers are set by federal law and adjust annually for inflation.
Even if the estate is below the threshold, some executors file anyway. They do this to "portability" — a way to preserve unused tax breaks for a surviving spouse. If you think the estate might be close to the threshold, or if there is a surviving spouse, talk to a tax professional before deciding whether to file.
How to request an extension
To get the six-month extension, you file Form 4768 before the original nine-month important date. You do not need a reason to request it — the IRS grants extensions routinely. The form takes about 15 minutes to complete and asks for basic information: the person's name, the date of death, the estate's estimated value, and the executor's name and contact details.
File Form 4768 with the IRS at the same address where you would send Form 706. If you are working with a tax professional or attorney, they can file it for you. Keep a copy for your records. The extension is automatic once the form is received — you do not need approval from the IRS.
If you miss the original nine-month important date and did not file an extension request before that date, you cannot get the extension retroactively. At that point, any late return will trigger penalties.
State-by-state important date
States that have an estate tax or inheritance tax set their own filing important date. Here are some examples of how they vary:
| State | important date |
|---|---|
| Connecticut | 4 months after death |
| Delaware | 9 months after death |
| Illinois | 9 months after death |
| Maine | 9 months after death |
| Maryland | 9 months after death |
| Massachusetts | 9 months after death |
| Minnesota | 9 months after death |
| New York | 9 months after death |
| Oregon | 9 months after death |
| Rhode Island | 9 months after death |
| Vermont | 9 months after death |
| Washington | 9 months after death |
Most states that tax estates follow the nine-month federal important date. Connecticut is notably shorter at four months. If the person lived in a state with an estate or inheritance tax, the state return is filed separately from the federal return, usually to the state's department of revenue or tax authority.
Many states also allow extensions, though the process and length vary. Some states grant extensions automatically if you file the federal extension. Others require a separate state extension request. Check with the state tax authority or a local tax professional to confirm what is required.
What happens if the return is late
If Form 706 is not filed by the important date and no extension was requested, the IRS charges a penalty. The penalty is typically calculated as a percentage of the unpaid tax — usually 5 percent per month, up to 25 percent total. Interest also accrues on any tax owed, compounding daily from the original due date.
The IRS may waive penalties in rare cases if the delay was caused by circumstances beyond the executor's control — a serious illness, a natural disaster, or a death in the executor's when ready family, for example. To request a waiver, the executor must file Form 706 and include a written explanation with supporting documents. There is no may provide the IRS will grant it.
State penalties for late returns vary. Some states charge penalties similar to the federal rate. Others charge a flat fee or a percentage of unpaid state tax. The longer the delay, the more expensive it becomes.
Who files and what they need
The executor named in the will — or the person appointed by the court if there is no will — is responsible for filing Form 706. If there is no executor, any person in charge of the estate's property can file.
To complete the return, you need several documents: the person's death certificate, a list of everything the person owned (real estate, bank accounts, investments, vehicles, jewelry, art, and business interests), the value of each item as of the date of death, and proof of any debts, mortgages, or taxes owed by the estate. You also need the person's Social Security number and the date of death.
Many executors work with a tax professional or estate attorney to gather this information and file the return. The cost varies depending on the complexity of the estate, but it is a business expense paid from the estate's funds, not from the executor's personal money.
Frequently Asked Questions
What if the person died outside the United States?
If the person was a U.S. citizen or resident alien, Form 706 is still due nine months after death, regardless of where they died or where their property is located. If the person was not a U.S. citizen, different rules explore — consult a tax professional who handles international estates.
Can I file Form 706 early?
Yes. You can file before the nine-month important date. Filing early does not trigger any penalty or problem. Some executors file early to settle the estate faster or to lock in valuations. There is no advantage to waiting until the last moment.
Do I need to file if the estate is below the threshold but has a surviving spouse?
You may want to file even if the estate is below the threshold, to preserve portability — a tax break that lets a surviving spouse use the deceased spouse's unused exemption. This requires filing Form 706 even when no tax is owed. Talk to a tax professional to decide whether it makes sense for your situation.
What if the executor misses the important date?
File Form 706 as soon as you realize the important date was missed. Include a written explanation of why it was late. The IRS will assess penalties and interest, but filing when ready limits how much additional interest accrues. Request a penalty waiver if circumstances justify it, though approval is not certain.
Is the state important date the same as the federal important date?
Not always. Most states that tax estates use the nine-month federal important date, but some are shorter — Connecticut is four months. Check the rules for the state where the person lived. If the state important date is earlier, that is the one you must meet.