What Is IRS Form 706?

IRS Form 706 is used by executors of a decedent’s estate to calculate and report the federal estate tax owed and to determine the generation-skipping transfer (GST) tax liability, if applicable. The form plays a central role in estate administration, particularly for estates whose value exceeds the federal estate tax exemption threshold. The form must be filed within nine months after the date of death, with a possible six-month extension available by request.

This form not only determines if any estate tax is due but also serves to establish the estate’s value for future tax reporting purposes. Even if no estate tax is ultimately owed, Form 706 may still be required in cases where the estate wishes to make specific elections or transfer unused exemptions.

Purpose and Function

The primary function of Form 706 is to report the total value of a decedent’s estate and to calculate any federal estate tax due. It includes all assets owned by the decedent at the time of death, which may include real estate, securities, cash, business interests, personal property, and certain types of trust assets.

In addition to calculating estate tax liability, the form also accommodates reporting for the generation-skipping transfer tax — a separate tax imposed on transfers to beneficiaries who are more than one generation below the decedent (such as grandchildren). Form 706 is also used to elect portability of the deceased spouse’s unused exclusion (DSUE) amount to a surviving spouse. This provision allows the surviving spouse to use the decedent’s unused portion of the estate tax exemption.

Who Must File

Form 706 is generally required for estates of U.S. citizens or residents whose gross estate, plus adjusted taxable gifts and specific exemption amounts, exceeds the federal estate tax exemption amount in effect for the year of death. For deaths occurring in 2025, for example, the federal exemption amount is $13.99 million.

Even if the total estate value is under the exemption threshold, the executor may choose to file Form 706 to elect portability of the DSUE amount. This is often done for planning purposes, particularly in cases where the surviving spouse’s estate may exceed the exemption in the future.

Key Components of the Form

Form 706 is lengthy and consists of multiple schedules and sections. Each part is designed to provide a detailed accounting of the estate’s assets, deductions, and tax credits.

• Part 1 summarizes the estate's gross value and provides information about the decedent and the executor.
• Schedules A through I break down specific categories of assets such as real estate (Schedule A), stocks and bonds (Schedule B), and annuities (Schedule I).
• Schedule J covers funeral expenses, debts, and certain administrative costs.
• Schedule K includes deductions for mortgages and liens.
• Schedule M allows for the marital deduction, enabling the estate to deduct amounts left to a surviving spouse.
• Schedule O deals with charitable deductions.
• Schedule R and R-1 relate to the generation-skipping transfer tax.

Each schedule requires careful documentation and valuation. Appraisals are often necessary for non-liquid assets such as real estate or closely held business interests.

Deadlines and Extensions

The standard deadline for filing Form 706 is nine months after the date of the decedent’s death. Executors can request a six-month filing extension using Form 4768, though this does not extend the time to pay any tax due. Interest and penalties may apply for late payments, so executors often pay a good-faith estimate of any potential liability even if they’re still compiling the return.

Common Uses and Elections

Form 706 also facilitates a number of important elections:

• Portability Election: If a surviving spouse is to inherit the unused exemption of the deceased spouse, Form 706 must be filed to elect portability. This is true even if no estate tax is due.
• Alternate Valuation Date: Executors may elect to use a valuation date six months after the date of death instead of the date of death itself, if doing so reduces the value of the estate and the tax owed.
• Special Use Valuation: Certain real property used in a family farm or closely held business may be valued at a reduced amount for estate tax purposes.
• Qualified Family-Owned Business Deduction (QFOBI): Though largely obsolete due to increases in the estate exemption, this election is still referenced in some filings.

These elections must be made on a timely and properly completed Form 706. Missing the deadline or failing to follow proper procedures can result in a loss of benefits.

Importance in Estate Planning

Form 706 plays a critical role in the estate planning process. While the lifetime exemption has risen significantly over the years, the form remains relevant not only for wealthy estates but also for strategic purposes such as portability planning. Filing the form when not strictly required may still yield long-term tax benefits for surviving spouses and heirs.

Proper preparation of Form 706 often involves coordination between estate attorneys, tax professionals, and appraisers. Errors or omissions can lead to audit risks or loss of tax-saving opportunities.

The Bottom Line

IRS Form 706 is more than a tax form — it is a foundational document in the administration and taxation of large estates. It determines the estate’s federal tax liability, enables key elections, and ensures compliance with federal estate and GST tax rules. Even when no tax is due, filing may be essential to preserve portability or finalize asset valuations. For estates nearing or exceeding the exemption amount, accurate and timely filing of Form 706 is essential for both compliance and effective estate planning.