Oklahoma Child Support Calculator 2026: How Much Will I Pay?

The Short Answer

How much will you pay? Our Oklahoma child support calculator gives fathers a fast estimate under the state’s Income Shares model. “All child support shall be computed as a percentage of the combined gross income of both parents” (43 O.S. § 118D(A)). First, Oklahoma combines both parents’ gross monthly incomes. Then it looks up the base support amount for that combined income on the schedule in § 119. Each parent is responsible for a share in proportion to his or her share of the combined income.

Overnights matter too: when each parent has “at least one hundred twenty-one (121) overnights of parenting time per twelve-month period,” the parenting-time adjustment in 43 O.S. § 118E can lower the paying parent’s amount, and a parent with more than 205 overnights cannot be ordered to pay.

The worksheet then adds the children’s health insurance premium and work-related child care on top. The guideline amount is presumptively correct: 43 O.S. § 118(A) creates “a rebuttable presumption … that the amount of the award which would result from the application of the following guidelines is the correct amount.” The estimate below follows selected formulas from the official OKDHS workbook. Treat it as a starting point, not your final court-ordered amount.

2026 status: The Legislature’s quadrennial review of the guidelines required by 43 O.S. § 119.1 took place this year; DHS lists the current guidelines’ effective date as May 1, 2026 and the next review for May 1, 2030.

We found no 2026 enactment changing §§ 118 through 120, and the two 2026 bills on the subject (SB 1452, a proposed presumption of joint custody, and SB 1453, which would have eliminated support between equal-time joint custodians) died in the Senate Judiciary Committee. Oklahoma family law can still change through new legislation, so before relying on any recent or pending statutory change, confirm the effective date and final text with an Oklahoma family law attorney.

Run Your Numbers

First, enter both parents’ gross monthly incomes, the number of children, and the overnight split. This simplified estimator follows selected formulas from the official OKDHS workbook for cases without income adjustments. It does not replace the official worksheet, and it does not determine the court-ordered paying parent. Also, some inputs require individual worksheet review and will not produce a number.

Prefer to see the math worked by hand? Our guide to how Oklahoma courts calculate child support walks through three real scenarios, dollar by dollar. It covers a standard case, the 121-night threshold, and true 50/50.

How the Guidelines Define Income

The number the calculator produces is only as good as the income figures that go into it, and the statute decides what counts. “Gross income” includes “earned and passive income from any source, except as excluded” (43 O.S. § 118B(A)(1)). Overtime and supplemental income are not automatically counted at last year’s peak: the court includes “such overtime and supplemental income as the court deems appropriate,” or uses “the average of the gross monthly income for the time actually employed during the previous year” (§ 118B(C)(1)).

For a self-employed father, income is business income “less ordinary and reasonable expenses,” and “a determination of business income for tax purposes shall not control” (§ 118B(D)(1)–(2)). A parent who is voluntarily unemployed or underemployed can have income imputed; one factor the court may consider is what the parent could earn at minimum wage for “not less than twenty-five (25) hours per week” (§ 118B(C)(3)(b)), and no income is imputed to a parent incarcerated for more than 180 days except in the contempt and victim-offense situations the statute lists (§ 118B(C)(2)).

Three adjustments change the inputs before the schedule is applied. A deduction for other children you support requires that the documented period of support “not be less than twelve (12) months” (§ 118C(D)(1)(a)).

The children’s health insurance premium is allocated between the parents in proportion to income and added to the base obligation (§ 118F(H)(1)), but only if the premium “does not exceed five percent (5%) of the gross income of the responsible parent” (§ 118F(D)(1)); when no insurance is available at a reasonable cost, cash medical support is capped at “five percent (5%) of the gross monthly income of the obligor, whichever is less” (§ 118F(F)(2)).

Work-related child care is “added to the base child support order” (§ 118G(C)). Uninsured medical expenses are shared after the fact, with proof due within “forty-five (45) days” of the explanation of benefits and payment due within 45 days after that (§ 118F(I)).

Overnights and the Parenting-Time Adjustment

Overnights are counted, not estimated. An “overnight” is a period in which the child is with the parent for “at least twelve (12) hours, and that parent has made a reasonable expenditure of resources for the care of the child” (43 O.S. § 118A(10)). The adjustment in § 118E starts when each parent has at least 121 overnights per twelve-month period and multiplies the base obligation by 2 at 121–131 overnights, 1.75 at 132–143, and 1.5 at 144 or more before allocating it.

Two limits protect the paying parent: “in no event shall the amount of child support ordered to be paid by a parent exceed the amount which would otherwise be ordered” without the adjustment, and “in no event shall the provisions of this paragraph be construed to authorize or allow the payment of child support by a parent having more than two hundred five (205) overnights” (§ 118E(D)(5)).

The adjustment is “not mandatory, but presumptive” (§ 118E(C)), and it cuts both ways: a parent who does not actually exercise the overnights the order assumes can have the adjustment taken away and a judgment entered for the support that went unpaid (§ 118E(E)). When the children follow different schedules, the statute uses an “annual average of parenting time with all of the children” (§ 118E(A)(2)), which this estimator does not model.

Deviations and Agreed Amounts

The guideline amount can be changed, but only on the terms in § 118H. The court may deviate only “if the deviation is in the best interests of the child” and, in addition, the guideline amount is unjust or inappropriate, or “the parties are represented by counsel and have agreed to a different disposition,” or one party is represented and the deviation benefits the unrepresented party (§ 118H(B)); the order must contain “specific findings of fact” supporting the deviation (§ 118H(C)).

An agreement between the parents is a starting point, not a decision: as the Oklahoma Supreme Court noted in Parham v. Parham, 2010 OK 24, “an agreement of the parties as to child support is not binding upon the court.” Parham also notes that parents have some latitude to agree on special terms for modifying child support, but their agreement cannot take away the court’s power to modify child support, and any such term is enforced only if it serves the child’s best interests.

Oklahoma Child Support Modification

Child support does not automatically update as circumstances change. To modify an existing order, you must file a motion with the court and show “a material change in circumstances,” which 43 O.S. § 118I(A)(1) describes as including “an increase or decrease in the income of the parents,” changes in the child’s needs, and incarceration of a parent for more than 180 consecutive days.

There is no universal 15% threshold in the statute, and a change in the schedule alone is not a material change (§ 118I(A)(2)). DHS also offers an informal review and adjustment process in which the other parent must provide the requested financial information “within forty-five (45) days of the request” (§ 118I(D)(2)).

Key rule: “A child support order shall not be modified retroactively” (§ 118I(B)(1)). A modification takes effect “on the first day of the month following the date the motion to modify was filed” (§ 118I(A)(3)), and the Court of Civil Appeals has held that “child support orders may not be modified retroactively and are prospective only in their application” (Ward v. Ward, 1995 OK CIV APP 51, 895 P.2d 749). So if you lose your job or your income drops, file immediately; every month you wait is a month at the old number.

Incarceration exception: “After November 1, 2021, there shall be a rebuttable presumption that an obligor who is incarcerated for a period of one hundred eighty (180) or more consecutive days is unable to pay” (§ 118I(E)). The obligation is “abated without court action effective the first day of the month following the date of entry” into incarceration. The presumption does not apply where the incarceration results from “indirect contempt of court for failure to pay child support … or for any offense for which the obligee’s dependent child or the obligee was a victim” (§ 118I(E)(4)).

When Support Ends, and What Arrears Cost

Under 43 O.S. § 112(E), support continues “until the child reaches eighteen (18) years of age,” and if the child is still in high school full time, “until the child graduates from high school or until the age of twenty (20) years, whichever occurs first.” The statute adds that “no hearing or further order is required to extend support” in that situation.

Past-due support “shall draw interest at the rate of two percent (2%) per year” from the date each payment becomes delinquent (43 O.S. § 114). The official number is always the one on the DHS Child Support Computation Form: “A child support computation form shall be signed by the judge and incorporated as a part of all orders” (§ 120(A)).

Frequently Asked Questions

Related Guides for Oklahoma Fathers

Keep going with our guides on how 50/50 custody affects child support and when child support legally ends in Oklahoma. Then read the step-by-step worksheet walkthrough, or meet our child support attorneys in Tulsa and Oklahoma City.

Sources and Legal Citations

• 43 O.S. § 118 — Child support guidelines; rebuttable presumption (OSCN)
• 43 O.S. §§ 118A, 118B, 118C, 118D, 118F, 118G, 118H, 119, 119.1, and 120 (Oklahoma Legislature, Title 43 compilation)
• 43 O.S. § 118E — Parenting time adjustment (OSCN)
• 43 O.S. § 118I — Modification of child support (OSCN)
• 43 O.S. § 112 — Duration of support (OSCN)
• 43 O.S. § 114 — Interest on past-due support (OSCN)
• Oklahoma DHS Child Support Services — Guidelines and Computation page
• Official DHS Child Support Computation Excel Worksheet (download)
• Oklahoma DHS — Quadrennial Review of the Child Support Guidelines (effective May 1, 2026; next review May 1, 2030)
• Parham v. Parham, 2010 OK 24, 236 P.3d 74 (agreements as to child support are not binding on the court; modifiability of consent decrees)
• Ward v. Ward, 1995 OK CIV APP 51, 895 P.2d 749 (no retroactive modification)
• SB 1452 (2026) — proposed rebuttable presumption of joint custody; died in the Senate Judiciary Committee
• SB 1453 (2026) — proposed bill to eliminate child support between parents with equal-time joint custody; died in the Senate Judiciary Committee

Last reviewed October 2026. This page is legal information for Oklahoma fathers, not legal advice about a specific case.