504-I: 2025 Form 504-I Application for Extension of Time to File an Oklahoma Income Tax Return Individuals (2025)

Who files this form

For tax year 2025, individuals need Form 504-I to request more time to file when they owe additional Oklahoma income tax or do not have a federal extension.

If you have an automatic federal extension and owe no additional Oklahoma tax, Oklahoma honors that extension. Provide a copy of the federal extension when you file your Oklahoma return.

• Spouses filing separate returns must each file an extension application.
• Corporations, partnerships and fiduciaries use Form 504-C instead.
• Electing pass-through entities use Form 504-PTE instead.

When it's due

For tax year 2025, the form gives these timing rules but does not print a specific calendar filing date:

• Extension applications must be postmarked on or before the income tax return's filing due date, or before the automatic federal extension expires.
• At least 90% of the tax liability must be paid by the return's original due date for the extension to be valid.
• An extension cannot exceed half the accounting period, such as six months for a 12-month tax year.
• Active military members serving outside the United States or confined to a hospital receive an automatic extension to the 15th day of the third month following their return to the United States or release from the hospital.

What you'll need

Have the following information ready to complete Form 504-I:

• Your name, mailing address and Social Security number, plus your spouse's name and Social Security number for a joint return.
• Your total Oklahoma income tax liability, which you may estimate.
• Oklahoma income tax withheld, estimated tax payments, any prior-year overpayment allowed as a credit, and other expected payments and credits.
• The amount you are paying and the extension dates requested on the form.

When you file your Oklahoma return, provide a copy of the applicable federal or Oklahoma extension. If you pay the extension electronically, keep the payment confirmation number and provide a copy of Form 504-I with your income tax return.

How to file

1. Enter your identifying information and the extension dates requested on the form.
2. Complete the tax computation. Enter your estimated total tax liability on line 1, or “0” if you do not expect to owe tax. Add lines 2, 3 and 4 on line 5, then subtract line 5 from line 1 for the balance due on line 6. Enter your payment on line 7.
3. Sign and date the form. Both spouses must sign a joint application, even if only one had income.

By mail: Send Form 504-I with payment, if applicable, to:

Oklahoma Tax Commission

PO Box 26890

Oklahoma City, OK 73126-0890

Electronic payment: Make an extension payment at oktap.tax.ok.gov. Some electronic payment services charge a convenience fee. Keep your confirmation number. If you pay electronically, do not mail Form 504-I. Instead, provide a copy when you file your income tax return.

Common mistakes

• Treating the extension as extra time to pay. It only extends the time to file. At least 90% of the tax liability must be paid by the original due date for the extension to be valid.
• Leaving line 1 blank. You must enter an amount, including “0” if you do not expect to owe tax.
• Missing a spouse's signature. Both spouses must sign if filing jointly, even if only one had income.
• Mailing Form 504-I after paying electronically. Do not mail it in that situation. Provide a copy with your income tax return instead.
• Using the wrong extension form. Corporations, partnerships and fiduciaries use Form 504-C. Electing pass-through entities use Form 504-PTE.

Questions people ask

Do I need Form 504-I if I already have a federal extension?

Not if you owe no additional Oklahoma income tax. Oklahoma honors the automatic federal extension in that situation. Provide a copy of it when you file your Oklahoma return.

Does this extension give me more time to pay?

No. It extends only the time to file. A 5% delinquent penalty may be charged if at least 90% of your total tax liability is not paid by the original due date. Interest is charged at 1.25% per month from the original due date until the tax is paid.

Can I estimate my tax liability?

Yes. Line 1 allows an estimate of your total income tax liability. You must enter an amount. If you do not expect to owe tax, enter “0”.

How much additional filing time can I request?

The extension cannot be longer than half the accounting period covered by your return. For a 12-month tax year, that means a six-month extension.

Official sources

• https://oklahoma.gov/content/dam/ok/en/tax/documents/forms/individuals/current/504-I.pdf