Oklahoma — Personal Income Tax

Oklahoma residents must file an individual income tax return if they are required to file a federal income tax return, regardless of income source. Every Oklahoma resident who has sufficient gross income to require filing a federal return is required to file an Oklahoma return.

Residents who are not required to file a federal return are not required to file an Oklahoma return. However, residents may still file to claim a refund of Oklahoma withholding or estimated tax payments, or to claim refundable credits.

Part-year residents have the same filing requirements as residents during their period of Oklahoma residency. During the period of non-residency, an Oklahoma return is required if gross income from Oklahoma sources is $1,000 or more.

Source: Oklahoma Tax Commission, 2025 Form 511 Packet

A resident individual for Oklahoma income tax purposes is a natural person domiciled in Oklahoma. Any person who spends more than seven months of the taxable year in Oklahoma is presumed to be a resident absent proof to the contrary. A person who spends less than seven months in Oklahoma is presumed to be a part-year resident absent contrary proof. Domicile is defined as a person's true, fixed, and permanent home and, once established, continues until a new domicile is established.

Source: 68 O.S. § 2353(4); Oklahoma Tax Commission, 2025 Form 511-NR Packet

For tax year 2026 and subsequent years, Oklahoma imposes graduated income tax rates on individuals. Single filers and married filing separately pay 0% on the first $3,750 of taxable income, 2.5% on income from $3,751 to $4,900, 3.5% on income from $4,901 to $7,200, and 4.5% on income above $7,200. Married filing jointly, head of household, and surviving spouse filers pay 0% on the first $7,500, 2.5% on income from $7,501 to $9,800, 3.5% on income from $9,801 to $14,400, and 4.5% on income above $14,400.

House Bill 2764 (2025) includes a trigger mechanism under which all rates may decrease by 0.25 percentage points when specified revenue conditions are met, as certified by the State Board of Equalization each February. Successive certifications can reduce rates by additional 0.25-point increments until rates reach zero.

Source: Oklahoma Tax Commission, 2025 Tax Legislation Summary

For tax year 2025, Oklahoma allows a standard deduction of $6,350 for single filers and married filing separately, $12,700 for married filing jointly and qualifying surviving spouse, and $9,350 for head of household. Taxpayers who claim the standard deduction on their federal return must also claim the Oklahoma standard deduction; those who itemize federally must itemize for Oklahoma purposes.

Source: Oklahoma Tax Commission, 2025 Form 511 Packet

Every nonresident individual having Oklahoma gross income of $1,000 or more for the taxable year must file an Oklahoma income tax return, except as otherwise provided for in the Pass-Through Entity Tax Equity Act of 2019. This filing requirement is set forth in 68 O.S. § 2368(C)(2), which states that "every nonresident individual having Oklahoma gross income for the taxable year of One Thousand Dollars ($1,000.00) or more shall file an Oklahoma income tax return."

The $1,000 threshold applies to gross income from Oklahoma sources—before deductions or expenses are applied. This is a substantially lower threshold than the federal filing requirement and lower than many other states' nonresident thresholds. Nonresidents use Form 511-NR (Oklahoma Nonresident/Part-Year Income Tax Return) to report Oklahoma-source income.

Oklahoma-source income for nonresidents. According to the Oklahoma Tax Commission, a nonresident is taxed on the following sources of income: salaries, wages, and commissions for work performed in Oklahoma; income from rental of Oklahoma real or tangible personal property; income from business, trade, profession, or occupation carried on in Oklahoma; distributive shares of partnership income and S corporation income from entities doing business in Oklahoma; and gain from the sale of Oklahoma real property. Oklahoma oil and gas royalty income is also subject to Oklahoma withholding and taxation for nonresidents.

Calculation and proration method. The Oklahoma taxable income of a nonresident individual is calculated as if all income were earned in Oklahoma, using Form 511-NR. The taxpayer begins with federal adjusted gross income (AGI) and then applies the Oklahoma adjustments allowed under 68 O.S. § 2358 to arrive at AGI from all sources. The AGI from all sources is used to determine taxable income. After taxable income is calculated, it is prorated using a percentage: the Oklahoma-source AGI divided by AGI from all sources. This prorated amount yields the Oklahoma tax. This methodology ensures that nonresidents pay Oklahoma tax only on the portion of their income attributable to Oklahoma.

Exception for electing pass-through entity members. Under 68 O.S. § 2355.1P-4(E), a nonresident individual who is a member of an electing pass-through entity is not required to file an Oklahoma income tax return if, for the taxable year, the only source of income allocable or apportionable to Oklahoma for the member (or, if filing a joint return, for the member and spouse) is from one or more electing pass-through entities, and each electing pass-through entity files and pays the taxes due under the Pass-Through Entity Tax Equity Act of 2019 (68 O.S. § 2355.1P-1 et seq.).

Composite partnership returns. A nonresident partner may elect to be included in a composite partnership return in lieu of filing an individual Oklahoma return. The Oklahoma Tax Commission has promulgated rules for partnership composite returns; see OAC 710:50-19-1.

Voluntary filing for refunds. Nonresidents who do not have an Oklahoma filing requirement but had Oklahoma tax withheld or made estimated tax payments may file Form 511-NR to claim a refund of those payments.

Source: 68 O.S. § 2368

Source: 68 O.S. § 2355.1P-4

Source: 68 O.S. § 2358

Source: Oklahoma Tax Commission, 2025 Form 511-NR Packet

Source: Oklahoma Tax Commission, Income Tax Help Center

Oklahoma individual income tax returns are generally due on April 15 following the close of the calendar year, consistent with the federal deadline. Under 68 O.S. § 2368(H)(1), all individual returns filed on paper (except corporate returns and individual returns filed electronically) on a calendar-year basis shall be due on or before the fifteenth day of April following the close of the taxable year. The statute further provides that if the Internal Revenue Code provides for a later due date for individual returns, the Oklahoma Tax Commission shall accept returns filed by that later date and treat them as timely filed.

Electronic filing deadline extension (administrative). The Oklahoma Tax Commission grants an administrative extension for individual taxpayers who file their Oklahoma return electronically. According to the Tax Commission, if you file your return electronically—through a preparer or the internet—your due date is extended to April 20. This five-day extension is an administrative accommodation, not a statutory requirement. The Tax Commission further states that any payment of taxes due on April 20 must be remitted electronically in order to be considered timely paid; if the balance due on an electronically filed return is not remitted electronically, penalty and interest will accrue from the original April 15 due date.

Federal automatic extension. Oklahoma administratively honors the federal automatic extension when no additional Oklahoma tax is owed. The Oklahoma Tax Commission states: "If you have a valid extension of time to file your federal return and no Oklahoma tax is owed, your federal extension automatically extends the due date of your Oklahoma return." A copy of the federal extension must be enclosed with the Oklahoma return when filed. This policy recognizes that the Oklahoma return cannot be completed until the federal return is completed.

Oklahoma-specific extension (Form 504-I). When a taxpayer's federal return is not extended or an Oklahoma tax is owed, an extension of time to file the Oklahoma return can be granted by filing Form 504-I, Application for Extension of Time to File an Oklahoma Income Tax Return for Individuals. According to the form instructions, an extension of time to file is not an extension of time to pay the tax. The extension will not be granted unless 90% of the tax liability is paid on or before the original due date of the return.

Form 504-I sets forth the following requirements:

• An extension cannot be granted for more than one-half the accounting period covered by the individual (i.e., a six-month extension for calendar-year filers).
• Applications for extensions of time must be postmarked on or before the due date for filing the income tax return, or before the expiration of the automatic federal extension.
• When the Oklahoma return is filed, a copy of the Oklahoma extension (Form 504-I) must be attached.
• If the extension payment is made electronically through the Oklahoma Taxpayer Access Point (OkTAP), the taxpayer should not mail Form 504-I; when filing the income tax return, the taxpayer should provide the electronic payment confirmation.

Military exception. Form 504-I provides that an automatic extension, without request, is granted to members of the active military service serving outside the United States or confined to a hospital. This extension is granted to the 15th day of the third month following their return to the United States or their release from a hospital.

Weekend and holiday adjustments. Although not specified in 68 O.S. § 2368, the Oklahoma Tax Commission follows standard administrative practice that when a filing deadline falls on a Saturday, Sunday, or legal holiday, the deadline is extended to the next business day.

Source: 68 O.S. § 2368

Source: Oklahoma Tax Commission, Help Center – Income Tax

Source: Form 504-I, Application for Extension of Time to File