Child Support Calculations in Oklahoma

Oklahoma calculates child support using the Income Shares model under 43 O.S. §118, ensuring children receive the same proportion of parental income they would have enjoyed had the family remained intact. Whether you're navigating an uncontested or contested divorce, understanding Oklahoma's unique parenting-time adjustment formula and modification thresholds is essential.

The Income Shares Model

Oklahoma's Income Shares approach combines both parents' adjusted gross income (AGI), then uses the statutory Schedule of Basic Child Support Obligations to determine the total support amount. This amount is divided between parents proportionally based on their AGI shares.

• Statutory schedule: Codified in 43 O.S. §119, covering combined monthly incomes from $50 to $15,000
• Combined income cap: $15,000/month—above this, courts add a discretionary amount based on the child's needs and standard of living
• Basic obligation covers: Housing, food, transportation, basic education, clothing, and entertainment

Calculating Adjusted Gross Income

Under 43 O.S. §118B, gross income includes both earned and passive income:

• Employment income: Wages, salary, tips, commissions, bonuses, severance, military pay
• Self-employment: Gross receipts minus ordinary and necessary business expenses (IRS accelerated depreciation excluded)
• Passive income: Dividends, pensions, rent, interest, trust income, Social Security, workers' compensation, unemployment
• Fringe benefits: Company car, housing, room and board that reduce personal living expenses

Excluded from income: Means-tested public assistance (TANF, SSI, SNAP), child support received for other children, and DHS Adoption Assistance subsidies.

AGI adjustments: Deduct court-ordered spousal support actually paid, support for prior-born children, and 75% of a hypothetical support amount for qualifying in-home children under 43 O.S. §118C.

Imputing Income for Voluntary Unemployment

If a parent is voluntarily unemployed or underemployed, courts may impute income based on:

• Industry wages and available hours
• Education, training, and ability to work
• Minimum wage at not less than 25 hours per week
• Lifestyle suggesting unreported income
• Caretaker duties for a disabled relative preventing work

Incarceration rule: For incarceration exceeding 180 consecutive days, courts use actual income (typically $0) unless incarceration is for contempt for failure to pay support or an offense against the child/obligee.

Parenting-Time Adjustment (PTA)

Under 43 O.S. §118E, a parenting-time adjustment applies when the noncustodial parent has at least 121 overnights per year:

• 121–131 overnights: Combined base × 2.0 multiplier
• 132–143 overnights: Combined base × 1.75 multiplier
• 144+ overnights: Combined base × 1.5 multiplier

The cross-credit formula calculates each parent's share of the adjusted base, multiplies by the percentage of time the child spends with the other parent, then offsets to determine the net payment.

Critical protections: The PTA cannot increase support beyond the non-PTA calculation, and no support can be ordered against a parent with more than 205 overnights (56%+ of nights).

Failure to exercise: If the obligor doesn't actually exercise the claimed overnights, the court may enter a judgment for underpaid amounts and suspend the PTA for 12 months.

Split Custody Calculations

When each parent has primary custody of at least one child:

• Calculate a separate guideline obligation for each household
• The parent with the larger obligation pays the difference to the other
• PTA may apply within each calculation if the 121-overnight threshold is met

Estimate Your Oklahoma Child Support

Use our calculator below for an estimate. For official calculations, use the Oklahoma DHS Excel Calculator, which judges require to be attached to all support orders.

Add-Ons: Medical Support and Childcare

Oklahoma adds specific costs to the basic support obligation under 43 O.S. §118F:

• Health insurance: "Reasonable" if the premium attributable to the child doesn't exceed 5% of the insuring parent's gross income and is accessible (within 60 miles)
• Cash medical: If no insurance is available, courts order $115/child per month, prorated by income and capped at 5% of the obligor's gross
• Work-related childcare: Actual annualized costs allocated pro rata by AGI under 43 O.S. §118G
• Transportation: Courts may divide long-distance parenting-time travel costs proportionally

Parents must notify each other within 45 days of childcare cost changes. Courts can allow a parent to provide care during the other's work periods if it significantly reduces costs.

Deviations from Guidelines

Under 43 O.S. §118H, courts may deviate with written findings explaining why deviation serves the child's best interests:

• Extreme economic hardship
• Extraordinary educational or medical needs
• Special quantifiable expenses (private school, camps, travel for activities)
• Foster/agency custody with a permanency plan for reunification

Duration of Support

Under 43 O.S. §112:

• Standard termination: Age 18
• High school continuation: Until graduation or age 20, whichever comes first, if the child is a full-time student
• Disabled adult children: Courts may order indefinite support if the child requires substantial care due to mental/physical disability that existed by age 18

Modification Requirements

Oklahoma allows modifications upon material change in circumstances under 43 O.S. §118I:

• CSS threshold: At least 20% change in amount AND at least $30/month difference
• Effective date: First day of the month after the motion is filed
• 36-month review: Child Support Services notifies parties every three years of their right to request review
• TANF cases: Automatic review every three years without request

Incarceration exceeding 180 days is a recognized ground for modification. CSS routinely seeks a $0 current support order during qualifying incarceration (unless for contempt or crimes against the child/obligee).

Enforcement and Arrears Interest

Oklahoma employs multiple enforcement tools through Child Support Services:

• Income withholding: Immediate wage garnishment (up to 50-65% of disposable earnings)
• Tax intercepts: Federal ($500 threshold for non-assistance) and state ($50 threshold)
• License suspension: Driver's, professional, and recreational licenses
• Passport denial: For qualifying arrearages
• Liens and bank levies: Financial Institution Data Match (FIDM) quarterly
• Credit reporting: Periodic arrearage reporting to credit bureaus
• Contempt: Willful failure may result in sanctions or incarceration

Arrears interest: Oklahoma charges 2% simple interest per year under 43 O.S. §114. Interest begins accruing the first day of the month after arrears exceed one month's current support. CSS does not charge interest on unpaid cash medical support.

Social Security Benefits Credit

Title II Social Security benefits received by a child are:

• Added to the income of the parent on whose account the benefit is paid
• Credited toward that parent's support obligation
• If the benefit exceeds the guideline amount, monthly support may be reduced to $0
• Benefits based on the child's own disability are not attributed to either parent

Key Takeaways

• Income Shares model: Both parents' AGI determines support under 43 O.S. §§118-119
• $15,000/month cap: Courts add discretionary amounts above the schedule cap
• No formal Self-Support Reserve: Low-income cases handled through the schedule's low-income entries
• 121-overnight threshold: Minimum for parenting-time adjustment
• No support from parent with 205+ overnights: Protects majority-time caregivers
• 2% simple arrears interest: One of the lowest rates nationwide
• 20%/$30 modification threshold: Dual requirement for CSS-initiated changes
• Support to 18 or 20: Extended for full-time high school students

For more information about Oklahoma divorce processes, see our Oklahoma divorce timeline and filing checklist. For property division information, review our Oklahoma marital property guide.