When are Forms 1065 and 1120-S due?

Who must file

Form 1065 is an information return for a partnership. A partnership generally does not pay tax on its income; profits and losses pass through to the partners, who report them on their own returns. Every domestic partnership must file Form 1065 unless it neither receives income nor incurs any expenditures treated as deductions or credits.

A multi-member LLC that is classified as a partnership has the same filing requirement. File Form 1120-S only if the entity elected to be an S corporation by filing Form 2553, the IRS accepted that election, and the election remains in effect.

The March 15, 2027 due date

A domestic partnership must file Form 1065 by the 15th day of the 3rd month after its tax year ends. An S corporation must file Form 1120-S by the same rule. For a calendar-year partnership or S corporation, that date is March 15.

If the due date falls on a Saturday, Sunday or legal holiday, you may file on the next day that is not a Saturday, Sunday or legal holiday. The 2025 form instructions print the 2025 calendar-year due date as March 16, 2026, because March 15, 2026 was a Sunday. March 15, 2027 is a Monday, so the calendar-year 2026 return is due March 15, 2027. The 2026 form instructions were not yet published when this page was checked.

Schedule K-1

Attach a copy of each Schedule K-1 to the return you file with the IRS, keep a copy, and give each partner or shareholder a copy. Publication 509 says to provide that copy by the 15th day of the 3rd month after the tax year ends: March 15 for a calendar year, the same day as the return.

Form 7004

File Form 7004 by the regular due date of the return for an automatic 6-month extension of time to file. For a calendar-year Form 1065 or Form 1120-S due March 15, that extended filing date is September 15. September 15, 2027 is a Wednesday. Form 7004 does not extend the time to pay any tax due. Pay what is owed by the original due date.

E-file

Partnerships must e-file Form 1065 and related forms if they file 10 or more returns of any type during the tax year, including information, income tax, employment tax and excise tax returns. S corporations must e-file Form 1120-S if they file 10 or more returns of any type during the calendar year. Partnerships with more than 100 partners must e-file in any event.

Late-filing penalties

For a late or incomplete Form 1065 or Form 1120-S, the IRS charges a base penalty for each month or part of a month, up to 12 months, multiplied by the number of partners or shareholders during the tax year. For a return due March 15, 2027, that base rate is $260, from Rev. Proc. 2025-32 in Internal Revenue Bulletin 2025-45. There is a separate $340 penalty for each failure to furnish a correct Schedule K-1 when due. For an S corporation return on which tax is due, an additional percentage penalty can apply.

Common questions

Is this the same date as my Form 1040?

No. A calendar-year partnership or S corporation return is due March 15, not April 15. April 15 is the usual due date for Form 1040 and for a calendar-year C corporation Form 1120.

Does Form 7004 give me more time to pay?

No. Form 7004 extends the time to file the return. It does not extend the time to pay any tax due.

What if March 15 is a weekend?

You may file on the next day that is not a Saturday, Sunday or legal holiday. March 15, 2027 is a Monday, so that rule does not move the 2027 date.

Is this tax advice?

No. It is general information from IRS pages checked on November 13, 2026. Rules change, so check the sources before you act.