511-EF: 2025 Form 511-EF Oklahoma Individual Income Tax Declaration for Electronic Filing (2025)
Oklahoma · Oklahoma Tax Commission · Used for tax years 2025
Form 511-EF is the declaration for electronically filing a 2025 Oklahoma individual income tax return. It records income, tax, payments and credits, and any refund or balance due, along with taxpayer and preparer declarations.
Who files this form
Form 511-EF is the declaration for an electronically filed 2025 Oklahoma individual income tax return.
Most taxpayers do not need to mail this form or any documentation to the Oklahoma Tax Commission (OTC). If your electronic return requires no additional forms or documentation, keep Form 511-EF for your records.
If your return includes any of the forms or supporting documents listed on page 2, you must either attach that documentation as a PDF to your electronic return or mail it with Form 511-EF as a cover page. If your software does not support PDF attachments, mail the required items with Form 511-EF.
When it's due
For tax year 2025, the form lists these payment deadlines:
- Electronic payment: April 20.
- Non-electronic payment: Submit payment with Form 511-V on or before April 15.
If the Internal Revenue Code provides a later due date, payment by that later date is considered timely. If the due date falls on a weekend or legal holiday when OTC offices are closed, payment is due the next business day.
What you'll need
Use your 2025 Form 511 or Form 511-NR to complete the tax amounts on Form 511-EF. You will also need your identifying information, filing status and total number of exemptions. For a joint return, include your spouse’s information and signature.
Send the following forms or supporting documents if they are part of your return:
- Form OW-8-P-SUP-I, Annualized Income Installment Method for Individuals.
- Form 511-NOL or 511-NR-NOL, Oklahoma Net Operating Loss.
- Form 573, Farm Income Averaging.
- FTAC’s Form, Oklahoma Volunteer Firefighter Tax Credit.
- A copy of the other state’s income tax return if you file Form 511-TX.
- Any Oklahoma statements containing additional information required by the Form 511 or 511-NR packet instructions.
How to file
Complete Part One using whole dollars only and check that the amounts match the corresponding lines of your 2025 Oklahoma return. Sign and date the taxpayer declaration. Both spouses must sign a joint return. Part Three is for the electronic return originator (ERO) and paid preparer.
Required supporting documentation may be sent as PDF attachments with your electronically filed return. If you mail the documentation, use Form 511-EF as the cover page and send it to:
Oklahoma Tax Commission
Oklahoma City, OK 73194
If no additional forms or documentation are required, do not mail Form 511-EF. Keep it for your records.
Payments are separate. Do not enclose payment with Form 511-EF. For a mailed payment, use Form 511-V and the address printed on that voucher. Electronic payment options are available at oktap.tax.ok.gov. For a balance-due return with an electronic payment, complete line 6b.
Common mistakes
- Mailing unnecessary returns or statements. Do not mail your Oklahoma Form 511 or 511-NR, federal Form 1040, or withholding statements such as W-2, W-2G or 1099 forms.
- Mailing Form 511-EF when nothing else is required. Keep it for your records instead.
- Enclosing payment with Form 511-EF. Use Form 511-V for a mailed payment, or pay electronically.
- Missing a spouse’s signature. Both spouses must sign a joint return.
- Not paying the full balance on time. The taxpayer remains liable for unpaid tax and applicable interest and penalties.
Questions people ask
Do I need to mail Form 511-EF after filing electronically?
Usually not. If no additional forms or documentation are required, keep it for your records. If you mail required supporting documentation, include Form 511-EF as the cover page.
Can I send required documents electronically?
Yes. The listed supporting documents may be attached as PDFs to your electronically filed return. If your software does not support PDF attachments, mail them with Form 511-EF.
Does my spouse need to sign?
Yes. Both spouses must sign Form 511-EF for a joint return.
What does the direct-deposit consent say?
It authorizes direct deposit as designated in the electronic portion of your 2025 Oklahoma return. For a joint return, it also irrevocably appoints the other spouse as an agent to receive the refund.