Federal returns · 2027 dates

Check the filing date for Form 1065 and Form 1120-S

A calendar-year partnership or S corporation lands on 15 March. In 2027 that day is a Monday. A calendar-year C corporation is expected on 15 April 2027, with an extension to 15 October 2027. The checker applies the 15th-day rule, the next business day, and a Form 7004 date labelled expected.

Check a filing date Who files in March

Business deadline checker

Choose how the entity is taxed, the year-end, and, when it matters, how many partners or shareholders there are. The page works out a filing date in this browser. Nothing is stored and nothing is sent.

Enter the return

Not tax or legal advice. Informational only. Check the IRS instructions. This form does not file anything and does not compute a payment.

Use this for a partnership, or for a multi-member LLC only if it is taxed as a partnership.

A calendar year ends on 31 December. The default is 31 December 2026.

Used for the indicative late-filing amount on Form 1065 and Form 1120-S.

Leave blank to skip the total. A fraction of a month counts as a month. Maximum 12.

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Constants and sources

  • Form 1065 and Form 1120-S: 15th day of the 3rd month after the year ends. Calendar year: 15 March. 15 March 2027 is a Monday. Instructions for Form 1065. Instructions for Form 1120-S.
  • Form 1120: 15th day of the 4th month. Calendar year ending 31 December 2026: 15 April 2027, extension 15 October 2027, both expected. A June 30 year beginning before 2026 uses the 3rd month and a 7-month extension. The sentence "6 months for tax years beginning in 2026" is only for a June 30 C corporation. Instructions for Form 1120. Treas. Reg. 1.6072-2.
  • Form 7004: generally 6 months if filed by the original due date. E-file is available (MeF). The extension does not extend the time to pay tax that is due. Extended dates are labelled expected. Instructions for Form 7004.
  • Late filing, returns filed in 2027: $260 per partner (section 6698) or shareholder (section 6699) per month, maximum 12, under Rev. Proc. 2025-32. Check the current IRS amount. Separate cited figures, not added into that total: 60-day income-tax minimum, the lesser of $535 or 100 percent of the tax; K-1 general payee-statement amount $340; intentional disregard, the greater of $690 or the percentage in the revenue procedure. Rev. Proc. 2025-32 (PDF).
  • E-file: the 10-return rule applies to both Form 1065 and Form 1120-S. More than 100 partners applies to Form 1065 only. There is no 100-shareholder e-file threshold for Form 1120-S.
  • Schedule K-1 is furnished no later than the due date of the return. Whether Form 7004 moves that date is not verified. Weekend or federal holiday: next business day. The foreign-books rule is omitted. State dates are not calculated. Constants checked 17 October 2026. Re-check planned 1 January 2027.

Calendar-year picture for a 31 December 2026 year-end

Dates for a year ending 31 December 2026. All dates are expected.
ReturnWhoFiling dateExtended date
Form 1065Partnership, or multi-member LLC taxed as a partnership15 March 2027, Monday15 September 2027, expected
Form 1120-SS corporation15 March 2027, Monday15 September 2027, expected
Form 1120C corporation15 April 2027, expected15 October 2027, expected

Guides

Ten short guides. The March date is first. The tools page names no vendors.

Who Files Form 1065 or 1120-S by March 15, 2027

Partnerships and multi-member LLCs file Form 1065, S corporations Form 1120-S. For calendar-year entities the due date is expected on March 15, 2027.

Form 7004: 6-Month Extension for 1065 and 1120-S

Form 7004 gives an automatic 6-month extension to file 1065 and 1120-S (expected September 15, 2027), but it does not extend the time to pay any tax.

Late 1065 and 1120-S Penalty: $260 per Person (2027)

Late 1065 and 1120-S penalty: $255 per person per month for returns due 2026, $260 for returns due 2027 (Rev. Proc. 2025-32), up to 12 months.

S Corp vs C Corp Deadlines 2027: 1120-S vs 1120

For calendar-year entities, 1120-S is expected due March 15, 2027 and Form 1120 April 15, 2027. Extension dates and what differs, from IRS instructions.

Form 1065 E-Filing: 10-Return Rule and 100+ Partners

The 1065 instructions require e-filing if the partnership files 10 or more returns of any type, or has over 100 partners. Waiver and limits.

Form 2553 and Form 1120-S: What Must Be True First

Form 1120-S requires an S election: Form 2553 filed, accepted by the IRS and still in effect. Checklist with the 2 months 15 days rule and late relief.

All 10 guides

What the checker leaves out

No state date

Annual reports and franchise taxes are not calculated. A federal date is not a state date.

No payment amount

Form 7004 does not extend the time to pay tax that is due. The checker does not compute tax.

K-1 extension is open

The K-1 is due with the return. Whether the extension moves that date is not verified.