File Your S-Corp 1120-S Tax Extension Online and Avoid Costly Penalties

What is Form 1120-S?

Internal Revenue Service Form 1120-S, U.S. Income Tax Return for an S Corporation, is the annual tax return used by S-Corporations to report their income, deductions, credits, and other financial information to the IRS.

Unlike C-corporations, an S-Corporation generally does not pay federal income tax at the entity
level. Instead:

• The business reports its financial activity on Form 1120-S
• Each shareholder receives a Schedule K-1 (Form 1120-S)
• Shareholders report their share of profit or loss on their personal tax returns

Even if the business has no income or activity during the year, the S-Corporation is still required to file Form 1120-S annually to remain compliant.

When is the Deadline to File Form 1120-S?

S-Corporations must file Form 1120-S by the 15th day of the third month after the end of the tax year.

• Calendar-year S-Corporations: Due March 16, 2026 (March 15 falls on a Sunday, so the deadline moves to the next business day)
• Fiscal-year S-Corporations: The deadline is the 15th day of the third month after the fiscal
  year ends.

If your business does not operate on a calendar year, find your tax due date here.

How to File 1120-S Extension?

S-Corporations that need more time to file Form 1120-S can request an extension of time by
filing Form 7004.

S-Corporations that file Form 7004 on or before the original deadline will get up to 6 months of additional time from the IRS to file Form 1120-S. This extension is automatic, so you are not required to provide any reason for requesting more time.

What are the Penalties Associated with S-Corp Tax Return 1120-S?

An IRS penalty may be imposed on S-Corporations that have not filed their 1120-S or didn’t get an extension by the deadline. The penalty amount depends on whether or not the S-Corporation owes taxes. Here are the penalty rates according to the IRS.

• Late Filing Penalty (No Tax Due): For tax year 2025 filings (filed in 2026):
  • $245 per shareholder, per month
  • Charged for up to 12 months
• Late Payment Penalty (Tax Due):
  • 5% of unpaid tax per month
  • Maximum penalty: 25% of the unpaid tax
• Interest Charges: Interest accrues on unpaid tax from the original due date, even if an extension
  is filed.

S-Corporations may also be subjected to penalties for not paying the tax due balance within the deadline (even if they have got an extension for filing 1120-S).

Easily File S-Corp Tax Extension with ExpressExtension

ExpressExtension is an IRS-authorized e-file provider that helps businesses request Form 7004 extensions online.You can complete and e-file your extension in minutes:

• Step 1: Enter business information and choose Form 7004
• Step 2: Select the form (1120-S) for which you need to request an extension
• Step 3: Enter the form details, complete the tax payment (EFW or EFTPS), and transmit the form to the IRS.

You’ll receive an electronic acknowledgement once the IRS accepts the extension.

Avoid IRS late filing penalties by e-filing your S-Corp extension now!