K-1 Tax Form for Inheritance: Boxes, IRD, and Late Filings

If you received a Schedule K-1 after inheriting from an estate or trust, you owe federal income tax on the income shown on that form — interest, dividends, capital gains, rents, and other items the estate or trust earned and allocated to you — reported box by box on your Form 1040 and its schedules. The K-1 tax form for an inheritance situation is Schedule K-1 (Form 1041), and it exists because the estate or trust passed its taxable income through to you rather than paying tax on it internally.¹

Why the Estate or Trust Sent You a K-1

When someone dies, their estate becomes a separate taxpayer. Assets sitting in the estate keep producing income: a brokerage account throws off dividends, a rental collects rent, a bank account earns interest. The estate files Form 1041 to report all of it.² The executor then decides how much of that income to distribute out to beneficiaries and how much the estate keeps. Your K-1 reports the portion allocated to you.

Trusts work the same way. If assets flowed into a trust — one the deceased created during life or one established by will — the trustee files Form 1041 and issues K-1s to beneficiaries who received or were entitled to receive distributions.¹

One point trips people up: you owe tax on K-1 income whether or not the cash has hit your account. If the estate earned $8,000 in dividends and the executor allocated $4,000 to you, you report $4,000 even if no check has been cut. The tax follows the allocation.

The Inheritance Itself Is Not on the K-1

The K-1 reports income the estate earned. It does not report the value of the property you inherited. Under federal law, most inherited assets take a basis equal to their fair market value on the date of death, so tax on any gain only kicks in when you sell.³ Inherited traditional IRAs and 401(k)s are the major exception and come to you on a Form 1099-R from the custodian, not on a K-1. And a handful of states impose their own inheritance tax on the transfer itself, separate from any federal income tax on K-1 income. Those are all separate questions from what the K-1 asks of you.

Where Each K-1 Box Goes on Your Return

The K-1 preserves the character of each type of income, so interest stays interest, dividends stay dividends, and long-term capital gains keep their preferential rate treatment. The box numbers map to specific lines on Form 1040 and its schedules:¹

Box 1, interest income: Form 1040, line 2b, and Schedule B if total interest exceeds $1,500.
Box 2a, ordinary dividends: Form 1040, line 3b, and Schedule B if total dividends exceed $1,500.
Box 3, net short-term capital gain: Schedule D, line 5.
Box 4a, net long-term capital gain: Schedule D, line 12.
Box 5, other portfolio and nonbusiness income: Schedule E, line 33. This is often where income in respect of a decedent appears.
Boxes 6 through 8, business income and rental income: Schedule E. The fiduciary should attach a supplemental schedule breaking these out by activity.⁴

Tax software handles the routing automatically. If you’re filing by hand, the beneficiary instructions that come with your K-1 include a column pointing to the correct 1040 line for each box.⁵

Income in Respect of a Decedent

Some income belongs to the deceased in principle but wasn’t received before death — unpaid wages, accrued bond interest, and distributions from traditional retirement accounts are typical examples. This is called income in respect of a decedent, or IRD. It doesn’t get a stepped-up basis. Whoever ends up receiving it pays income tax on it, at the same character it would have carried for the deceased.

On the K-1, IRD usually shows up in Box 5 if it doesn’t fit into an earlier box.⁶ The fiduciary should identify how much of Box 5 is IRD, because it can trigger a deduction. If the estate was large enough to owe federal estate tax, and some of that estate tax was attributable to the IRD items, you can claim a deduction for the estate tax allocable to your share of the IRD.⁷ The deduction goes on Schedule A as an itemized deduction. You’ll need information from the estate tax return to compute it, so ask the executor if your K-1 includes IRD and the estate paid estate tax.

Excess Deductions in the Final Year

When an estate or trust closes, its last-year deductions can exceed its last-year income. The leftover passes through to beneficiaries who succeed to the property, and appears in Box 11 of the final K-1.⁶ Each excess deduction keeps its character:

Box 11, Code A covers Section 67(e) expenses such as fiduciary fees — costs that exist only because the property was held in an estate. Claim them as an adjustment to income on Schedule 1 (Form 1040), line 24k. You don’t need to itemize.
Box 11, Code B covers non-miscellaneous itemized deductions. Claim them on the applicable line of Schedule A. You must itemize.

There’s no carryover. If your income that year isn’t high enough to absorb the deduction, the unused portion is lost. If the estate is winding down and timing is flexible, that’s worth raising with the executor before the final return is filed.

When the K-1 Shows Up After April 15

K-1s from estates and trusts frequently arrive after the individual filing deadline. Form 1041 is due April 15 for calendar-year filers, but executors routinely take a 5½-month extension that pushes their deadline to September 30.² Your K-1 won’t come out until the estate files, which can leave you without the numbers you need.

The cleaner option is to file Form 4868 for an automatic six-month extension on your own return, moving your filing deadline to October 15.⁸ The extension only covers filing. If you expect to owe tax on K-1 income, estimate it and pay by April 15 to avoid interest.

You can also file by April 15 using estimates and later file Form 1040-X to amend once the real K-1 arrives. That works when you’re confident the K-1 amounts will be small or the executor has given you a reliable preview. Either way, don’t ignore the K-1 when it does show up. The IRS gets its own copy from the estate, and unreported K-1 income is straightforward for the matching system to catch.

If You Think the K-1 Is Wrong

If a number on your K-1 looks wrong — income that seems too high, a missing deduction, or a distribution you don’t believe was yours — start with the executor or trustee. They can issue a corrected K-1 and amend Form 1041 if needed.

If you can’t resolve it, you’re required to file Form 8082, Notice of Inconsistent Treatment, with your return explaining why your numbers differ from the K-1.⁹ Filing Form 8082 protects you from accuracy-related penalties. If you just report different numbers without it, the IRS can add penalties on top of any additional tax.

The same form applies if the estate or trust never filed at all. If no Form 1041 was filed and no K-1 was ever issued, attach Form 8082 to your return explaining that, and report income based on the best information you have.

1
Internal Revenue Service. 2025 Instructions for Schedule K-1 (Form 1041) for a Beneficiary Filing Form 1040 or 1040-SR
2
Internal Revenue Service. 2025 Instructions for Form 1041
3
Office of the Law Revision Counsel. 26 USC 1014 – Basis of Property Acquired From a Decedent
4
Internal Revenue Service. Instructions for Form 1041 and Schedules A, B, G, J, and K-1 (2025)
5
Internal Revenue Service. 2025 Schedule K-1 (Form 1041)
6
Internal Revenue Service. Instructions for Schedule K-1 (Form 1041) for a Beneficiary Filing Form 1040 or 1040-SR
7
eCFR. 26 CFR 1.691(c)-1 – Deduction for Estate Tax Attributable to Income in Respect of a Decedent
8
Internal Revenue Service. Get an Extension to File Your Tax Return
9
Internal Revenue Service. About Form 8082, Notice of Inconsistent Treatment or Administrative Adjustment Request (AAR)