Form 1065 Due Date: When Partnership and LLC Returns Are Due

The Form 1065 due date is the deadline for partnership tax returns, and it is also the LLC filing due date for most LLCs with more than one owner, so the Form 1065 LLC question comes first below. This guide follows the 2025 Instructions for Form 1065: who files, the 1065 deadline for 2025 and 2026 returns, when partners get Schedules K-1 and K-3, the Form 7004 extension and what it cannot do, e-filing, and the IRC 6698 late filing penalty with the relief routes that still exist for small partnerships.

Who files Form 1065

The instructions start broad: “every domestic partnership must file Form 1065, unless it neither receives income nor incurs any expenditures treated as deductions or credits for federal income tax purposes.” LLCs that are classified as partnerships have the same filing requirements, so classification decides which return an LLC files. A domestic LLC that makes no election is a partnership if it has two or more members and is disregarded as separate from its owner if it has one (Treas. Reg. 301.7701-3(b)(1)). The same LLC can change its return, and its due date, by electing corporate or S corporation treatment:

Three points behind the table:

• Spouses. A married couple who jointly own and run an unincorporated business are generally partners who must file Form 1065. If both materially participate, file a joint return and hold the business outside any state-law entity, they can elect qualified joint venture status and report on separate Schedules C or F instead. The election is not available to a business held in an LLC.
• Elections change the deadline. An LLC taxed as an S corporation keeps the March date on Form 1120-S (see the S corp tax deadline); one taxed as a C corporation moves to the April C corp deadline. Whether an election makes sense is covered in S corp vs LLC.
• The no-activity exception is narrow. A partnership with no income but any deductible expense files. A partnership seeking certification as a qualified opportunity fund files even with no income or expenses.

Form 1065 due dates for 2025 and 2026

Partnership returns on the calendar year are due “on or before the 15th day of March,” and fiscal-year returns by the 15th day of the third month after the year closes (IRC 6072(b)). When that day is a Saturday, Sunday or legal holiday in the District of Columbia or the state where the return is filed, the instructions treat a return filed the next business day as timely, which is how 2025 returns got to March 16, 2026.

A fiscal-year partnership counts from its own year end: a year ending September 30 makes Form 1065 due December 15. A partnership cannot choose its year freely; it generally has to use the majority interest taxable year of its partners or another year the rules allow (IRC 706(b)). The 2025 Form 1065 covers calendar year 2025 and fiscal years that begin in 2025 and end in 2026. Every date for every entity type is on the business tax calendar.

When partners get Schedules K-1 and K-3

The Code requires each partner’s statement “on or before the day on which the return for such taxable year was required to be filed” (IRC 6031(b)), and the regulation measures that day “determined with regard to extensions” (Treas. Reg. 1.6031(b)-1T(b)). So K-1s are due March 16, 2026 for an unextended 2025 return and September 15, 2026 for an extended one; Publication 509 calls the September set the partners’ “final or amended (if required)” K-1s.

Schedule K-3 has its own clock

Schedule K-3 carries items of international tax relevance and follows the K-1 timeline when it is required (2025 instructions for Schedules K-2 and K-3). A domestic partnership can skip it under the domestic filing exception, which requires, among other things, telling partners no later than the K-1 date that they will not get a K-3 unless they ask. Timing then turns on the “1-month date,” one month before the partnership files:

• For calendar-year 2025 partnerships that extended, the IRS puts the latest 1-month date at August 17, 2026.
• A partner request received by that date means the partnership files the relevant parts of Schedules K-2 and K-3 and gives the requesting partner a copy on the day it files.
• A request received after that date does not cost the exception, but the partnership has to provide the requested K-3 within 1 month of receiving it. In the IRS example, a request received August 20, 2026 is answered by September 20, 2026.

On-time K-1s also keep a small partnership’s shortcuts

Question 4 of Schedule B on the 2025 Form 1065 excuses a partnership from Schedules L, M-1 and M-2, item F and item L of the K-1 when four conditions are all met: total receipts under $250,000, total assets under $1 million at year end, no Schedule M-3, and Schedules K-1 “filed with the return and furnished to the partners on or before the due date (including extensions).” The same four conditions now excuse Schedules K-2 and K-3, with notice to partners. Late K-1s fail the test.

Each K-1 (and K-3) furnished late or with missing or wrong information can draw a $340 penalty. For 2025 statements, the calendar-year maximum is $4,098,500, or $1,366,000 for a partnership with gross receipts of $5 million or less; intentional disregard raises each penalty to $680, or 10% of the items if greater, with no maximum. After the return’s due date, IRC 6031(b) also limits amending K-1 information, and a partnership under the BBA audit rules corrects a filed return through an administrative adjustment request, explained in how to amend a business tax return.

The partners’ own deadlines

Partners pick up their shares for the partnership year that ends within or with their own tax year (IRC 706(a)), so a calendar-year partnership’s 2025 K-1 belongs on each partner’s 2025 return. Those returns keep their own dates: April 15, 2026 for individuals, and the partnership’s extension does not move them. Treas. Reg. 1.6081-2(e) says an automatic extension of the partnership return “does not extend the time for filing a partner’s income tax return or the time for the payment of any tax due.” Individual partners waiting on a September K-1 therefore extend their own Form 1040 on Form 4868 and pay what they expect to owe in April. Tax on partnership income is paid by the partners, generally through their own quarterly estimated taxes, because a partnership generally pays no tax on its income.

Extending Form 1065 with Form 7004

A partnership gets one automatic six-month extension by filing Form 7004 with code 09 by the original due date: March 16, 2026 for 2025 returns and March 15, 2027 for 2026 returns, which moves the return and the K-1s to September 15. The regulation allows nothing beyond that: “No additional extension will be allowed” past the six months, apart from partnerships that keep their books outside the United States and Puerto Rico (Treas. Reg. 1.6081-2(a)). Form 7004 can be e-filed; the Form 7004 guide covers the lines and addresses.

Two partnership elections exist only on a return filed on time, extensions included, so a late return loses them for the year:

• Electing out of the BBA centralized audit regime on Schedule B-2, open to a partnership with 100 or fewer eligible partners (individuals, C corporations, S corporations, certain foreign entities and estates of deceased partners). A partnership with a partner that is another partnership, a trust or a disregarded entity cannot elect out.
• The qualified small business payroll tax election for the R&D credit, which a partnership makes at the entity level (IRC 41(h)(4)(C)) and which cannot be added on an amended return.

E-filing Form 1065

Since 2024, a partnership that files 10 or more returns of any type during the year, counting information returns such as Forms W-2 and 1099 and employment tax returns, must file Form 1065 electronically (Treas. Reg. 301.6011-3, updated by T.D. 9972). A partnership with more than 100 partners must e-file Form 1065 and its Schedules K-1 regardless. The Ogden Submission Processing Center considers hardship waivers, and partnerships whose partners’ religious beliefs conflict with the technology may file on paper with “Religious Exemption” written at the top of page 1.

The late filing penalty: $255 per partner per month

IRC 6698 applies when a partnership fails to file on time, counting extensions, or files a return that leaves out required information. The monthly amount is “the product of” a dollar figure and “the number of persons who were partners in the partnership during any part of the taxable year,” for each month or fraction of a month, up to 12 months. The dollar figure is $195 in the statute and indexed for inflation: $255 for returns required to be filed in 2026 (Rev. Proc. 2024-40) and $260 for returns required to be filed in 2027 (Rev. Proc. 2025-32). It is assessed against the partnership, not the partners, and the same section covers a partnership adjustment tracking report filed late under the BBA rules.

Illustration for a hypothetical calendar-year LLC with 4 members, taxed as a partnership:

The first row counts five periods: March 17 to April 16, then four more monthly periods, the last one running from July 17 to August 3. A partnership that filed Form 7004 and then missed September 15, 2026 is charged one month if it files by October 15, 2026, and another month for each month after that.

Relief: Rev. Proc. 84-35, automatic exemption and reasonable cause

Small partnerships. The IRS penalty manual, updated December 30, 2025, still applies Rev. Proc. 84-35 (IRM 20.1.2.4.3.1). It presumes reasonable cause for a late or incomplete return when all of these are true:

1. The partnership has 10 or fewer partners, counting a married couple filing a joint return as one.
2. Each partner is an individual, other than a nonresident alien, or the estate of a deceased partner.
3. Each partner’s share of income, deductions and credits is allocated in the same proportion as every other item.
4. Each partner reported its share of partnership income on a timely filed income tax return.

The manual tells IRS employees to warn that the penalty will be reassessed if a condition later proves false, such as a partner who filed late. The 4-member LLC above fits if its members are individuals who are not nonresident aliens, split every item by the same percentages and filed their own returns on time; one with a trust or a corporate member does not.

Everyone else can ask for reasonable cause relief. The Form 1065 instructions say to wait for the penalty notice and then send the explanation, not to attach it to the return.

Sources: IRS, 2025 Instructions for Form 1065; IRS, 2025 Form 1065; IRS, 2025 Partnership Instructions for Schedules K-2 and K-3 (Form 1065); IRS Publication 509 (2026), Tax Calendars; 26 U.S.C. 6072(b), returns of partnerships and S corporations; 26 U.S.C. 6031, return of partnership income; 26 U.S.C. 6698, failure to file partnership return; 26 U.S.C. 706, taxable years of partner and partnership; 26 U.S.C. 41(h), payroll tax election for qualified small businesses; 26 CFR 301.7701-3, classification of eligible entities; 26 CFR 1.6031(b)-1T, statements to partners; 26 CFR 1.6081-2, automatic extension for partnership returns; IRS, Rev. Proc. 2024-40 (amounts for returns filed in 2026); IRS, Rev. Proc. 2025-32 (amounts for returns filed in 2027); IRS, Internal Revenue Manual 20.1.2.4.3.1, Revenue Procedure 84-35 (December 30, 2025); IRS, IR-2026-83, automatic penalty relief (July 8, 2026); IRS, Administrative penalty relief (reviewed July 14, 2026). Rules, dates and amounts checked against these sources in September 2026. This is general information, not tax advice for your situation. Tax services are provided by licensed tax professionals under a separate engagement agreement. BEG does not provide tax advice.