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Oklahoma business tax extension

Oklahoma honors the federal extension for Form 512, and has its own extension form for a business without one. The federal extension is Form 7004, due for calendar-year corporations and for partnerships and S corporations. In general, an extension gives you more time to file, not more time to pay.

Last updated · From Oklahoma's own forms, instructions and laws, cited below

Does Oklahoma accept the federal extension?

A federal extension (Form 7004) also extends the Oklahoma return. Without a federal extension, file Form 504-C, Application for Extension of Time to File an Oklahoma Income Tax Return for Corporations, Partnerships and Fiduciaries.

Oklahoma's rules for each business return, as its own instructions and laws state them:

Corporations

Return
Form 512, Oklahoma Corporation Income Tax Return
Due date
30 days after the federal due date of Form 1120
Extension
A federal extension (Form 7004) also extends the Oklahoma return. Without a federal extension, file Form 504-C, Application for Extension of Time to File an Oklahoma Income Tax Return for Corporations, Partnerships and Fiduciaries. A federal extension extends the Oklahoma return only if no Oklahoma tax is owed; include a copy of the federal extension with the return. If tax is owed or there is no federal extension, file the Oklahoma form by the original due date. The extension cannot exceed seven months in total. It is valid only if 90% of the tax is paid by the original due date.
Payment
The tax is due by the original due date, even with an extension. To pay with the extension: Form 504-C with payment, or an electronic extension payment at oktap.tax.ok.gov.

S corporations

Return
Form 512-S, Oklahoma Small Business Corporation Income Tax Return
Due date
30 days after the federal due date of Form 1120-S
Extension
A federal extension (Form 7004) also extends the Oklahoma return. Without a federal extension, file Form 504-C, Application for Extension of Time to File an Oklahoma Income Tax Return for Corporations, Partnerships and Fiduciaries (Form 504-PTE for an electing pass-through entity). A federal extension extends the Oklahoma return only if no Oklahoma tax is owed; include a copy of the federal extension with the return. If tax is owed or there is no federal extension, file the Oklahoma form by the original due date. The extension cannot exceed seven months in total. It is valid only if 90% of the tax is paid by the original due date.
Payment
The tax is due by the original due date, even with an extension. To pay with the extension: Form 504-C (or Form 504-PTE) with payment, or an electronic extension payment at oktap.tax.ok.gov.

Partnerships

Return
Form 514, Oklahoma Partnership Income Tax Return
Due date
30 days after the federal due date of Form 1065
Extension
A federal extension (Form 7004) also extends the Oklahoma return. Without a federal extension, file Form 504-C, Application for Extension of Time to File an Oklahoma Income Tax Return for Corporations, Partnerships and Fiduciaries (Form 504-PTE for an electing pass-through entity). A federal extension extends the Oklahoma return only if no Oklahoma tax is owed; include a copy of the federal extension with the return. If tax is owed or there is no federal extension, file the Oklahoma form by the original due date. The extension cannot exceed six months.
Payment
The tax is due by the original due date, even with an extension. To pay with the extension: Form 504-C (or Form 504-PTE) with payment, or an electronic extension payment at oktap.tax.ok.gov.

Estates and trusts

Return
Form 513, Oklahoma Resident Fiduciary Income Tax Return (nonresident estates and trusts file Form 513-NR)
Due date
The 15th day of the 4th month after the tax year ends (April 15 for a calendar year)
Extension
A federal extension (Form 7004) also extends the Oklahoma return. Without a federal extension, file Form 504-C, Application for Extension of Time to File an Oklahoma Income Tax Return for Corporations, Partnerships and Fiduciaries. A federal extension extends the Oklahoma return only if no Oklahoma tax is owed; include a copy of the federal extension with the return. If tax is owed or there is no federal extension, file the Oklahoma form by the original due date. The extension cannot exceed half the accounting period (six months for a 12-month year).
Payment
The tax is due by the original due date, even with an extension. To pay with the extension: Form 504-C with payment, or an electronic extension payment at oktap.tax.ok.gov.

When a due date in Oklahoma falls on a weekend or legal holiday, it moves to the next business day. Oklahoma's holidays can differ from the federal ones, so a rule not tied to a federal date is given without a computed date.

When is the federal business extension due?

Corporations, S corporations, partnerships, multi-member LLCs, estates and trusts extend their federal return with Form 7004, filed by the return's original due date. The extension is automatic: no reason is needed and the IRS doesn't approve it. We e-file it for a flat $9.95. These are the 2027 dates for calendar-year 2026 returns:

Federal extension deadlines for calendar-year 2026 returns
ReturnFile the extension byExtended to
Form 1065 Partnerships & multi-member LLCs, Form 70046 months
Form 1120-S S corporations (and LLCs taxed as S corps), Form 70046 months
Form 1120 C corporations (and LLCs taxed as C corps), Form 70046 months
Form 1041 Estates & trusts, Form 70045½ months
Form 990, 990-EZ, 990-PF Tax-exempt organizations & private foundations, Form 8868May 15, 2027 is a Saturday6 months

Federal dates follow the IRS rule: a deadline on a weekend or legal holiday moves to the next business day. A fiscal-year business counts from its own year-end; see the fiscal-year deadline guide.

Tax-exempt organizations extend the 990 series with Form 8868, not Form 7004. Each return needs its own extension, so extending a business return does not extend its owners' personal returns.

Does an extension give more time to pay?

No. A federal extension moves the filing deadline only: tax owed is due by the original due date, and the IRS charges interest and the late-payment penalty on anything paid after it. Oklahoma's instructions say the same for its returns: a Oklahoma extension doesn't move the payment deadline. More in does an extension give you more time to pay?

Where are Oklahoma's forms and instructions?

On the Oklahoma Tax Commission website, which has the current forms, instructions and online services. The rules on this page are summarized from the sources below. We e-file the federal extension; the Oklahoma return and any Oklahoma extension request go to the state.

Oklahoma extension FAQ

Does Oklahoma accept the federal business tax extension?

A federal extension (Form 7004) also extends the Oklahoma return. Without a federal extension, file Form 504-C, Application for Extension of Time to File an Oklahoma Income Tax Return for Corporations, Partnerships and Fiduciaries. A federal extension extends the Oklahoma return only if no Oklahoma tax is owed; include a copy of the federal extension with the return. If tax is owed or there is no federal extension, file the Oklahoma form by the original due date. The extension cannot exceed seven months in total. It is valid only if 90% of the tax is paid by the original due date.

When is the Oklahoma Form 512 due?

30 days after the federal due date of Form 1120.

Does a Oklahoma extension give more time to pay?

No. The tax is due by the original due date, even with an extension. To pay with the extension: Form 504-C with payment, or an electronic extension payment at oktap.tax.ok.gov.

Does a Oklahoma business still need a federal extension?

Yes, to get more time for its federal return: Form 7004, filed by April 15, 2027 for a calendar-year corporation or March 15, 2027 for a partnership or S corporation. Oklahoma honors that federal extension for the state return too.

Sources

Filing a federal business extension this season?

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