Specialized Returns for Individuals · Estate tax

Estate filing requirements and due dates (Form 706, Form 1041)

Verification 2026 Verified
tax year · reviewed 2026-08-20 · Draft for I. Ohu review

A death produces up to three separate returns, filed by the same person, on three different schedules, under three different thresholds. Two of them are income tax returns and one is a transfer tax return, and the commonest administrative failure is treating the last as optional because no tax is owed. It is often optional. It is also the return on which the portability election lives, and the one whose threshold lifetime gifts have quietly lowered.

The rule

Three returns. The decedent’s final Form 1040 for the part of the year up to death; Form 1041 for the estate as a taxable entity from the day after death; and Form 706 for the estate tax. The personal representative signs and files all three where each is required.

Form 1041: when. $600 of gross income for the taxable year for a domestic estate; a trust files on any taxable income, or on $600 of gross income whatever the taxable income; and either files where any beneficiary is a nonresident alien, whatever the income (IRC § 6012(a)(3), (4), (5))^TY2026 And the 15th day of the fourth month following the close of the taxable year — 15 April for a calendar year estate (IRC § 6072(a))^TY2026

Form 1041: an estate may choose its year. an estate may adopt a fiscal year, and a fiscal year must be a period of 12 months ending on the last day of a month other than December — so an estate's first year can be short but cannot end mid-month (IRC § 441(e))^TY2026 This is the one election in estate administration that is genuinely free and frequently missed — a fiscal year lets income and distributions be aligned across two calendar years, and the choice is made simply by filing the first return on that basis.

Form 706: when. a return is required where the gross estate of a citizen or resident exceeds the basic exclusion amount in effect for the calendar year of death — $60,000 of United States situs property for a nonresident who is not a citizen (IRC § 6018(a))^TY2026 9 months after the date of death (IRC § 6075(a))^TY2026

And the threshold is not what it appears. the filing threshold is reduced, but not below zero, by post-1976 adjusted taxable gifts and by any specific exemption allowed under the repealed IRC § 2521 for gifts after 8 September 1976 — so an estate below the basic exclusion amount can still be required to file (IRC § 6018(a)(3))^TY2026 An estate of $15,000,000 for a decedent dying in calendar year 2026 — the IRC § 2010(c)(3)(A) basic exclusion amount as raised by Pub. L. 119-21 § 70106, indexed from calendar year 2026 and rounded to the nearest $10,000 under § 2010(c)(3)(B)^TY2026 less the client’s lifetime taxable gifts is the real line, and the executor will not know where it sits without the gift tax history.

One election merges two of the returns. where the executor and the trustee of a qualified revocable trust both elect, the trust is treated and taxed as part of the estate rather than as a separate trust (IRC § 645(a))^TY2026 It runs until 2 years after the date of death where no estate tax return is required, and 6 months after the final determination of the chapter 11 liability where one is (IRC § 645(b)(2))^TY2026

Extensions of time to file. the Secretary may grant a reasonable extension of time to file, and outside the case of taxpayers abroad no such extension may exceed 6 months (IRC § 6081(a))^TY2026

Extensions of time to pay are separate, and longer. up to 12 months for estate tax shown on the return under the general rule, and for reasonable cause up to 10 years from the IRC § 6151(a) payment date — with a separate 4-year limit for a deficiency, unavailable where the deficiency is due to negligence, intentional disregard or fraud (IRC § 6161(a)(1), (a)(2), (b)(2), (b)(3))^TY2026 Where the estate holds a closely held business, where an interest in a closely held business exceeds 35 percent of the adjusted gross estate, the executor may elect to pay the attributable share of the tax in up to 10 equal installments (IRC § 6166(a))^TY2026

Current figures

Item	Rule
Form 1041 filing threshold	$600 of gross income for the taxable year for a domestic estate; a trust files on any taxable income, or on $600 of gross income whatever the taxable income; and either files where any beneficiary is a nonresident alien, whatever the income (IRC § 6012(a)(3), (4), (5))^TY2026
Form 1041 due date	the 15th day of the fourth month following the close of the taxable year — 15 April for a calendar year estate (IRC § 6072(a))^TY2026
Estate fiscal year	an estate may adopt a fiscal year, and a fiscal year must be a period of 12 months ending on the last day of a month other than December — so an estate's first year can be short but cannot end mid-month (IRC § 441(e))^TY2026
Form 706 filing threshold	a return is required where the gross estate of a citizen or resident exceeds the basic exclusion amount in effect for the calendar year of death — $60,000 of United States situs property for a nonresident who is not a citizen (IRC § 6018(a))^TY2026
Threshold reduced by lifetime gifts	the filing threshold is reduced, but not below zero, by post-1976 adjusted taxable gifts and by any specific exemption allowed under the repealed IRC § 2521 for gifts after 8 September 1976 — so an estate below the basic exclusion amount can still be required to file (IRC § 6018(a)(3))^TY2026
Form 706 due date	9 months after the date of death (IRC § 6075(a))^TY2026
Basic exclusion amount	$15,000,000 for a decedent dying in calendar year 2026 — the IRC § 2010(c)(3)(A) basic exclusion amount as raised by Pub. L. 119-21 § 70106, indexed from calendar year 2026 and rounded to the nearest $10,000 under § 2010(c)(3)(B)^TY2026
Section 645 election	where the executor and the trustee of a qualified revocable trust both elect, the trust is treated and taxed as part of the estate rather than as a separate trust (IRC § 645(a))^TY2026
Section 645 applicable date	2 years after the date of death where no estate tax return is required, and 6 months after the final determination of the chapter 11 liability where one is (IRC § 645(b)(2))^TY2026
Extension of time to file	the Secretary may grant a reasonable extension of time to file, and outside the case of taxpayers abroad no such extension may exceed 6 months (IRC § 6081(a))^TY2026
Extension of time to pay	up to 12 months for estate tax shown on the return under the general rule, and for reasonable cause up to 10 years from the IRC § 6151(a) payment date — with a separate 4-year limit for a deficiency, unavailable where the deficiency is due to negligence, intentional disregard or fraud (IRC § 6161(a)(1), (a)(2), (b)(2), (b)(3))^TY2026
Closely held business deferral	where an interest in a closely held business exceeds 35 percent of the adjusted gross estate, the executor may elect to pay the attributable share of the tax in up to 10 equal installments (IRC § 6166(a))^TY2026
Portability election	made by the executor of the estate of the deceased spouse, on an estate tax return for that estate on which the amount is computed, filed within the time prescribed including extensions — and once made it is irrevocable (IRC § 2010(c)(5)(A))^TY2026

How it works in practice

Fix the dates in the first meeting. Death on a given day sets three clocks: the final Form 1040 on the ordinary individual schedule for that calendar year; Form 706 at nine months; and the estate’s first Form 1041 at the fourth month after whatever year end the executor chooses. Only one of those is negotiable, and it has to be chosen before the first return goes in.

Choose the fiscal year deliberately. A death in, say, October gives a choice between a short year to 31 December and a fiscal year running to the following 30 September. The second defers the estate’s first return by nine months, gives income time to be identified, and lets distributions carried out in the second calendar year be reported in the estate’s first year. It is worth a conversation, and it disappears once a calendar year return has been filed.

Check the gift history before concluding no Form 706 is required. Section 6018(a)(3) reduces the threshold by post-1976 adjusted taxable gifts. A client who gave away a substantial amount during life and left a modest estate may still be over the line, and the executor has no way to know without the prior Forms 709.

File Form 706 anyway if there is a surviving spouse. This is the recurring point across this section and it belongs here too: made by the executor of the estate of the deceased spouse, on an estate tax return for that estate on which the amount is computed, filed within the time prescribed including extensions — and once made it is irrevocable (IRC § 2010(c)(5)(A))^TY2026 An estate that files nothing loses that permanently.

Separate the two extensions. An extension of time to file Form 706 does not extend the time to pay the estate tax. Where liquidity is the problem, the request is under § 6161 — up to twelve months as of right on the amount shown, or up to ten years for reasonable cause — or under § 6166 if a closely held business qualifies.

Consider the § 645 election where there is a revocable trust. Most modern estates are administered through one, and without the election the trust files its own Form 1041 on a mandatory calendar year while the estate files on whatever year it chose. The election collapses them into one return with one year end, and the fiscal year advantage extends to the trust’s income as well.

The estate that had to file after all

A woman dies with a gross estate of $2,100,000. Her executor reads the filing threshold, compares it to the basic exclusion amount, and concludes no Form 706 is required.

Her Forms 709 show $14,000,000 of post-1976 adjusted taxable gifts. Under § 6018(a)(3) the threshold is reduced by that amount, so the line for her estate is $1,000,000, not $15,000,000 — and her $2,100,000 gross estate is over it. The return is required, and there is tax to compute, because those gifts are added back to the base under § 2001(b)(1)(B). Nothing about the estate itself signalled this; only the gift history did.

The fiscal year that was thrown away

A man dies on 3 November. His executor files the estate’s first Form 1041 for the period to 31 December, because that is what the software offered.

That election is now made and the estate is a calendar year taxpayer. Had the executor chosen a fiscal year ending 31 October, the first return would not have been due until the following 15 February, the estate would have had a full year to identify income, and a distribution made in the following spring could have been carried back into the first fiscal year on the Form 1041. None of that is available now, and nothing about the default was flagged as a choice.

Three returns, three deadlines

A woman dies on 12 March with wages and interest to that date, an estate that will receive royalties for several years, and a gross estate above the filing threshold.

Her final Form 1040 covers 1 January to 12 March and is due on the ordinary individual date for that calendar year. Form 706 is due nine months after death, in December. The estate’s first Form 1041 is due on the 15th day of the fourth month after the year end the executor selects — as early as the following April if a calendar year is chosen, or as late as the following July if a fiscal year to 28 February is. Three returns, one signatory, three different clocks, and only the third is under the executor’s control.

The extension that did not extend what mattered

An executor cannot value a partnership interest in time and obtains an extension to file Form 706. He takes this to mean the tax is not yet due and pays nothing at the nine-month mark.

Interest and the failure to pay addition run from the nine-month date regardless. Section 6081 extends the time to file; the time to pay is extended only under § 6161, which is a separate request requiring reasonable cause for anything beyond the twelve months available on the amount shown. He should have estimated the tax, paid it, and extended only the filing.

Assuming no tax means no return. The Form 706 threshold is the gross estate against the basic exclusion amount, before deductions — and the return is where the portability election lives.

Forgetting § 6018(a)(3). Lifetime gifts reduce the filing threshold. An executor who has not seen the decedent’s Forms 709 cannot say whether a return is required.

Treating the Form 1041 threshold as taxable income. It is measured on gross income for an estate (IRC § 6012(a)(3)) — and any beneficiary who is a nonresident alien triggers a return whatever the income (§ 6012(a)(5)).

Letting the first Form 1041 default to a calendar year. The choice of fiscal year is made by filing and cannot be undone at will.

Choosing a fiscal year that ends mid-month. IRC § 441(e) requires a fiscal year to end on the last day of a month other than December.

Confusing the extension to file with the extension to pay. Section 6081 is filing; § 6161 is payment. Interest runs from the original date either way.

Overlooking the § 645 election where a revocable trust exists. Without it, the trust is a separate calendar year filer and the estate’s fiscal year advantage does not reach the trust’s income.

How this has changed

The mechanics are old. Sections 6012, 6018, 6072, 6075, 6081 and 6161 have been substantially in their present form for decades, and Pub. L. 119-21 amended none of them. Section 645 arrived in 1997 and has not been materially altered since.

What has changed is the population of estates that file. The Form 1041 threshold is $600 — the IRC § 6012(a)(3) gross income threshold for an estate, which is not indexed and has stood at that figure since the 1954 Code, so inflation alone has steadily widened the population of estates required to file^TY2026 — so the number of estates required to file an income tax return has grown with inflation alone, and an estate holding a modest bank balance can clear it. The Form 706 threshold has moved in the opposite direction: at $15,000,000 for a decedent dying in calendar year 2026 — the IRC § 2010(c)(3)(A) basic exclusion amount as raised by Pub. L. 119-21 § 70106, indexed from calendar year 2026 and rounded to the nearest $10,000 under § 2010(c)(3)(B)^TY2026 very few estates are required to file at all, which is precisely why the portability election is missed so often.

The practical shape of the topic has therefore inverted. Form 706 used to be the return an executor worried about and Form 1041 the afterthought. Now Form 1041 is the return most estates actually have to file, and Form 706 is the one most estates should file voluntarily and do not.

Exam focus

Expect a date computation. Form 706 is nine months from death (IRC § 6075(a)); Form 1041 is the 15th day of the fourth month after the close of the estate’s taxable year (§ 6072(a)). Watch for a fiscal year in the facts, because the four-month count is from the year end and not from death.

Know the two thresholds and what they are measured against: gross income for Form 1041, and the gross estate against the basic exclusion amount for Form 706 — reduced by lifetime adjusted taxable gifts under § 6018(a)(3), which is the detail that distinguishes a prepared candidate.

Know that the personal representative signs all three returns, that an extension to file is not an extension to pay, and that a fiscal year must end on the last day of a month.

Check yourself

1. A domestic estate has gross income of $700 and taxable income of nil after deductions. Must it file Form 1041?

Answer: Yes. IRC § 6012(a)(3) requires a return from every estate whose gross income for the taxable year is $600 or more, regardless of what taxable income comes to after deductions.

2. A decedent dies on 8 June. The executor selects a fiscal year ending 31 March. When is the estate’s first Form 1041 due?

Answer: 15 July of the following year. IRC § 6072(a) sets the date at the 15th day of the fourth month following the close of the fiscal year, and the four months run from 31 March, not from the date of death.

3. A decedent’s gross estate is $3,000,000 and she made post-1976 adjusted taxable gifts of $13,500,000. Is a Form 706 required?

Answer: Yes. IRC § 6018(a)(3) reduces the filing threshold by adjusted taxable gifts, so the applicable figure is the basic exclusion amount less $13,500,000, and the gross estate exceeds it.

4. An executor obtains an extension of time to file Form 706. Does the estate tax remain due at nine months?

Answer: Yes. IRC § 6081 extends the time to file only. An extension of time to pay must be sought separately under § 6161, and interest runs from the original date in any event.

5. May an estate adopt a taxable year ending on 15 September?

Answer: No. IRC § 441(e) defines a fiscal year as a period of 12 months ending on the last day of a month other than December, so a year end must fall on the last day of a month.

Change log

2026-08-20Initial draft. Sets out the three returns a death produces and their deadlines — the final Form 1040, the estate's Form 1041 under IRC §§ 6012(a)(3) and 6072(a), and Form 706 under §§ 6018(a) and 6075(a) — with the § 6018(a)(3) reduction of the filing threshold by lifetime gifts, the § 441(e) constraint on an estate's fiscal year, the § 645 election, and the extensions available under §§ 6081 and 6161.