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Extended Your Taxes? What's Due on October 15, 2026, and What Isn't

Joseph Moreau · October 12, 2026

Frustrated business owner sorting through receipts and tax paperwork at her desk.

If you asked for more time to file this spring, October 15, 2026 is probably on your radar. But not every business files that day, and an extension only gives you more time to file. It doesn't give you more time to pay. Here's how to tell whether October 15 is your deadline and what to check before then.

Who files on October 15, 2026

The IRS fourth-quarter tax calendar lists two income tax returns for October 15, 2026:

  • Individuals: Form 1040, if you timely requested a 6-month extension. Sole proprietors and other owners who report business income on their personal return fall here.
  • Corporations: calendar-year Form 1120, if you timely requested a 6-month extension.

If you didn't request an extension, October 15 isn't your filing date for these returns.

Who doesn't file on October 15

Partnerships and S corporations

According to the IRS third-quarter tax calendar, extended calendar-year partnership returns (Form 1065) and S corporation returns (Form 1120-S) were due September 15, 2026.

Fiscal-year corporations

A corporation whose tax year doesn't follow the calendar year has its own due date. The Form 1120 instructions say a corporation generally files by the 15th day of the 4th month after its tax year ends. A corporation with a tax year ending June 30 files by the 15th day of the 3rd month.

Taxpayers in IRS-declared disaster areas

Some taxpayers in IRS-declared disaster areas have postponed deadlines. Relief applies only to the areas and dates named in each IRS notice. To find out whether it applies to you, look up your county on the IRS tax relief in disaster situations page and read the specific notice.

An extension to file isn't an extension to pay

This is where many owners get caught.

  • Individuals: the IRS extension page says the extension is only for filing your return, and any tax you owe was due by the April filing date.
  • Corporations: the Form 7004 instructions say Form 7004 doesn't extend the time to pay tax. A corporation must pay the unpaid tax on or before the return's due date. For Form 7004 filers, interest is charged on tax not paid by the regular due date, even with an extension.

If you underpaid in the spring, finding that out now gives you time to plan for it.

Your October 15 checklist

  1. Confirm which return you file and when it's due. Form 1040 and calendar-year Form 1120 with an extension are due October 15 (fourth-quarter calendar). Extended calendar-year Forms 1065 and 1120-S were due September 15 (third-quarter calendar). Fiscal-year corporations count from their own year-end (Form 1120 instructions).
  2. Confirm you actually have an extension. Individuals can get one by filing Form 4868, by paying online and indicating the payment is for an extension, or through IRS Free File. If you paid online, you'll get a confirmation number for your records (extension page). Corporations use Form 7004, which generally has to be filed by the return's regular due date (Form 1120 instructions, About Form 7004).
  3. Check for disaster relief in your area. Look up your county and the specific notice on the IRS disaster relief page before you count on any postponement.
  4. Check what was paid and what's still owed. Compare what you paid by the original due date with what your return will show. An extension doesn't extend the time to pay (extension page, Form 7004 instructions).
  5. Don't miss the payroll deposits due the same day. If you have employees, October 15 also has a semiweekly deposit for payments made October 7–9 and a monthly-rule deposit for September payments. If you use EFTPS, schedule payments by 8 p.m. ET at least one calendar day before the due date (fourth-quarter calendar).
  6. File by October 15. If you're on extension for Form 1040 or calendar-year Form 1120, that's the date on the IRS calendar.

Not sure your books are ready?

If October 15 is close and your numbers aren't where they need to be, start with Ramsha's free financial review. In about 30 minutes, you'll see what needs attention first: Get your free financial review.

Sources

This article is general information for US entrepreneurs and business owners, not tax, legal, or accounting advice. Rules depend on your situation, so check the IRS sources above or talk with a qualified tax professional before you act.