IRS Authorized E-file Provider for Tax Extension Forms

Oklahoma
State Business Income Tax Extension

Oklahoma (OK) Requires:

  • The State of Oklahoma accepts an approved federal extension Form 7004, rather than a separate state extension form.
  • If the business filed a Form 7004 and it was rejected by the IRS, they can file a Form 504-C with Oklahoma for a state extension.
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IRS Authorized E-file Provider for Tax Extension Forms

ExpressExtension supports the filing of Form 504 C with the State of Oklahoma.


  • Create Oklahoma Form 504 C
  • Fill in Form Details
  • Download & Print the Form

An Overview of Oklahoma State Business Income Tax Extension Forms

- Updated Feb 08, 2024 - 8.00 AM by Admin, ExpressExtension

Does Oklahoma support tax extension for business income
tax returns?

Yes. Oklahoma requires a separate tax extension Form to be filed with the state department apart from the federal tax extension Form 7004.

What Form does the state of Oklahoma require to apply for
an extension?

For Corporation

The businesses operating (as Corporation) in Oklahoma need to file Form 504-C with the state to obtain a 6-month extension of time to file their business income tax return with the state.

  • Form 504-C - Request for Six-Month Extension to File (for C Corporation)

For S-Corporation

The businesses operating (as S-Corporation) in Oklahoma need to file Form 504-C with the state to obtain a 6-month extension of time to file their S-corporate income tax return with the state.

  • Form 504-C - Request for Six-Month Extension to File (for S Corporation)

Note: Make sure to pay any taxes due along with the extension Form to avoid penalties and interest.

For Partnerships/Fiduciaries

Partnerships/Fiduciaries in Oklahoma need to file Form 504-C with the state to obtain a 6-month extension of time to file their partnership/fiduciary income tax return.

Note: Make sure to pay any taxes due along with the extension Form to avoid penalties and interest.

When is the deadline to file Form 504-C with the state of Oklahoma?

Oklahoma General Corporation Tax Extension

Oklahoma State General Business Corporation tax extension Form 504-C is due within the 15th day of the month following the Federal due date. For Calendar year taxpayers May 15th is the deadline.

To file an extension for Form 512, apply for an extension using Form 504-C on or before the same date the business tax return is due.

Form 504-C grants an automatic 6-month extension of time to file
Form 512-S.

Corporations will automatically receive a six-month extension only if they have paid at least 90% of the tax liability and timely filed Form 512-S.

Note: Make sure to pay any taxes due along with the extension Form to avoid penalties and interest.

Oklahoma S-Corporation

Oklahoma State Business S Corporation tax extension Form 504-C is due within 4 months and 15 days following the end of the corporation reporting period.

To file an extension for Form 512-S, apply for an extension using Form 504-C on or before the same date the business tax return is due.

Form 504-C grants an automatic 6-month extension of time to file
Form 512-S.

Corporations will automatically receive a six-month extension only if they have paid at least 90% of the tax liability and timely filed Form 512-S.

Note: Make sure to pay any taxes due along with the extension Form to avoid penalties and interest.

Oklahoma Partnership/Fiduciary Tax Extension

Oklahoma State Partnership/Fiduciary tax extension is due within 4 months and
15 days.

To apply for an extension, file Form 504-C on or before the deadline of your partnership/fiduciary tax return is due.

Form 504-C grants an automatic extension of time to file partnership/fiduciary
tax return.

Note: Make sure to pay any taxes due along with the extension Form to avoid penalties and interest.

How do I pay my balance due along with the extension Form?

You can choose to pay your balance due along with your return by using any one of the following options:

  • 90% of the tax liability must be paid by the original due date of the return to avoid a delinquent penalty charge of 5% for late payment.
  • An electronic payment is accepted for an extension payment at www.tax.ok.gov
  • Pay your 90% of the tax liability with the extension application,
    Form 504-C.
  • If you make your extension payment electronically, do not mail Form 504-C. When you file your income tax return, simply enclose a copy of Form 504-C.

Where do I mail the extension Form 504-C?

Mail Form 504-C Application for Extension of Time to File an Oklahoma Income Tax Return for Corporations, and Partnerships, with payment if applicable, to:

Address Icon
Oklahoma Tax Commission
Income Tax
PO Box 26890
Oklahoma City, OK 73126-0890