The deadline depends on when the person died and what type of return you're filing

An estate tax return (Form 706 for federal tax, or your state's equivalent) is due nine months after the date of death. If the person died on March 15, the return is due December 15 of the same year. This nine-month window is fixed by the IRS and does not change based on how complicated the estate is or how long it takes to gather documents.

You can request a six-month extension, which moves the deadline to 15 months after death. The extension does not give you more time to pay taxes owed — only more time to file the paperwork. Any estate taxes due still follow the original nine-month deadline, and unpaid taxes accrue interest and penalties after that date.

Not every estate needs to file a return. The return is required only if the estate's total value exceeds the federal exemption amount (which varies by year and changes with tax law). State estate taxes have their own, often lower thresholds. You need to know both the federal and your state's rules to determine whether filing is mandatory.

Key Takeaways

  • Federal estate tax returns are due nine months after the date of death, with a possible six-month extension available.
  • Taxes owed are due on the original nine-month deadline even if you request an extension to file the paperwork.
  • You only file a return if the estate exceeds the federal exemption threshold, which changes yearly and depends on when the person died.
  • State estate or inheritance taxes have separate deadlines and thresholds that may require filing even when federal returns are not required.

Federal exemption thresholds and when they apply

The federal estate tax exemption is the amount of an estate's value that is not subject to federal tax. In 2024, that exemption is $13.61 million per person. An estate worth less than that amount does not owe federal estate tax and generally does not need to file Form 706 with the IRS.

The exemption amount changes every year based on inflation. It also changed significantly in 2026 — under current law, the exemption drops to approximately $7 million per person (adjusted for inflation) unless Congress acts. If the person died before 2026, use the exemption amount that was in effect the year they died, not the current year's amount.

Even if the estate does not owe tax, you may still need to file Form 706 to report the estate's value for other reasons — for instance, to establish a stepped-up basis for inherited property, which can reduce capital gains taxes for heirs. An estate tax professional or the IRS can tell you whether filing is necessary in your situation.

State estate and inheritance tax deadlines

Twelve states and the District of Columbia have their own estate taxes. These states are Connecticut, Delaware, Illinois, Maine, Maryland, Massachusetts, Minnesota, New York, Oregon, Rhode Island, Vermont, and Washington. Each state sets its own exemption threshold, which is often much lower than the federal amount, and its own filing deadline.

Some states require the return within nine months of death, matching the federal deadline. Others allow more time. A few states require filing only if the federal return is filed. You cannot assume your state follows federal rules — you must check your state's specific requirements, usually through the state's department of revenue or taxation website.

If the person owned property in multiple states, you may need to file returns in more than one state. The executor or personal representative of the estate is responsible for knowing which states apply and meeting each deadline.

How to request a six-month extension

To extend the filing deadline, you file Form 4768 (Application for Extension of Time to File U.S. Individual Income Tax Return) with the IRS before the original nine-month deadline passes. You do not need a reason to request the extension — the IRS grants it routinely. The form takes a few weeks to process, and you should file it well before the nine-month mark to avoid any gap.

Filing Form 4768 extends only the deadline to submit the paperwork, not the deadline to pay taxes. If you know the estate will owe tax, you should estimate the amount and pay it by the original nine-month deadline. Unpaid taxes accrue interest at the current IRS rate (which changes quarterly) plus a failure-to-pay penalty of 0.5% per month.

Some states allow their own extensions if you file for a federal extension, but this is not automatic. Check your state's rules separately. If you miss the original deadline without filing an extension, penalties apply immediately, even if you file the return a few days late.

What happens if you miss the deadline

If the return is not filed by the nine-month deadline (or the extended deadline if you requested one), the IRS assesses a failure-to-file penalty. This penalty is typically 5% of the unpaid tax for each month the return is late, up to 25% total. Interest also accrues on any unpaid tax from the original due date forward.

Missing the deadline does not erase the tax obligation — it only adds costs. The IRS can also audit the estate or pursue collection action against the executor or heirs. If the estate is large enough to owe significant tax, the penalties and interest can be substantial.

If you realize you missed the deadline, file the return as soon as possible and contact the IRS or a tax professional about the penalties. In rare cases, the IRS may waive penalties if you can show reasonable cause for the delay, though this is not may provide.

Who files the return and what documents you need

The executor or personal representative of the estate — the person named in the will or appointed by the court — is responsible for filing the estate tax return. If there is no executor yet, the court appoints one. The executor may hire an accountant or tax attorney to prepare and file the return on their behalf.

To file Form 706, you need a complete inventory of everything the estate owned at the time of death: real estate, bank accounts, investments, retirement accounts, life insurance, vehicles, and personal property. You also need the fair market value of each item as of the date of death (or six months after death, if the estate chooses the alternate valuation date). Appraisals, bank statements, and property tax records provide this information.

You will also need the person's Social Security number, the date of death, and documentation of any debts, funeral expenses, or charitable gifts the estate made. The IRS provides a detailed worksheet with Form 706 that lists everything required.

When the estate is still being settled

The nine-month deadline applies whether or not the estate's assets have been distributed to heirs. Many estates take longer than nine months to settle — especially if there are disputes, property to sell, or tax issues to resolve. You still file the return on time, even if you do not yet know the final amounts or have not finished paying all debts.

You can file an amended return (Form 706-A) later if the estate's value changes after you file — for instance, if property sells for more or less than the appraised value, or if a lawsuit settles. The amended return must be filed within three years of the original deadline (or within 60 days of paying the tax, whichever is later).

If the estate is very complicated and you genuinely cannot gather the information needed by the nine-month mark, the six-month extension is your tool. Use it. Filing late without an extension is far more costly than requesting the extension upfront.

Frequently Asked Questions

Do I have to file an estate tax return if the person left no will?

Whether a will exists does not determine whether a return is required — the estate's total value does. If the estate exceeds the federal exemption threshold for the year of death, you file a return regardless of whether there was a will. The court will appoint an administrator to act as executor if no one was named in a will.

What if the person died on December 31 — is the return due the next year?

No. Nine months from December 31 is September 30 of the following year. The deadline is always nine calendar months from the date of death, regardless of what year that lands in. Mark the exact date on a calendar to be certain.

Can I file the estate tax return before the person's final individual income tax return is due?

Yes. The estate tax return (Form 706) and the person's final individual return (Form 1040) are separate filings with different deadlines. The final 1040 is due the following April 15. You can file Form 706 months before that. In fact, you often need to file the estate return first to determine what income the estate earned and what deductions apply.

What if the estate owes no tax but still has to file a return?

You still file Form 706 by the nine-month deadline. Even though no tax is owed, the IRS requires the return to document the estate's value and the calculation that resulted in no tax. This is common when the estate is just over the exemption threshold or when most of the estate passes to a surviving spouse (who may be exempt from tax).

Does the extension deadline change if the nine-month date falls on a weekend or holiday?

Yes. If the nine-month deadline falls on a Saturday, Sunday, or federal holiday, the deadline moves to the next business day. The same rule applies to the extended deadline. Check the IRS website or a tax calendar for the exact date in your situation.