How is Child Support Calculated in Oklahoma?

Oklahoma combines both parents' adjusted gross monthly incomes into one figure, looks up the result on a state guideline table, and splits the obligation between the parents based on each one's share of that combined income. Health insurance, work-related child care, and extraordinary medical costs get added on top and divided the same way. What makes Oklahoma distinct is its parenting time adjustment — a noncustodial parent with 121 or more overnights a year can qualify for a real reduction in their support obligation, built directly into the statute.

Oklahoma's income shares model: combine, then split

Oklahoma uses an income shares model under 43 O.S. §118. The idea behind income shares is that a child should generally receive the same proportion of parental income they would have received if both parents lived in the same household. To get there, courts add both parents' adjusted gross monthly incomes together, then figure out what percentage of that combined total each parent contributes.

That combined-income approach means both parents' earnings are part of the calculation from the first step, and both share responsibility for the basic obligation in proportion to what they earn. Oklahoma's guideline table, set out in 43 O.S. §119, runs from a combined income of $50 a month up to $15,000 a month. Above that ceiling, a judge sets the amount for the first $15,000 using the table, then adds an additional amount based on the family's circumstances.

The basic steps: table, split, add-ons

The calculation follows a consistent sequence set out in the statute and the official Oklahoma Child Support Services computation guide.

Step	What happens
1. Determine gross income	Each parent's gross monthly income is established under 43 O.S. §118B
2. Apply deductions	Permitted deductions, such as pre-existing support obligations to other households, are subtracted to get each parent's adjusted gross income
3. Combine incomes	Both parents' adjusted gross incomes are added together to get the combined monthly gross income
4. Find each parent's share	Each parent's income is divided by the combined total to get a percentage contribution
5. Look up the basic obligation	The combined income and number of children are matched against the Schedule of Basic Child Support Obligations in 43 O.S. §119
6. Split the basic obligation and add extras	Each parent's percentage share is applied to the basic obligation, then health insurance, child care, and extraordinary medical costs are added and divided the same way

This sequence produces the standard obligation before any parenting time adjustment is applied.

What counts as income in Oklahoma

Oklahoma's guidelines define gross income broadly under 43 O.S. §118B — most money coming in before taxes generally counts toward the calculation.

Income type	Generally included?
Wages, salaries, commissions, bonuses	Yes
Self-employment income	Yes — gross receipts minus ordinary business expenses
Pension, retirement, and Social Security income	Yes
Rental income and investment income	Yes
Alimony received	Yes
Means-tested public assistance (SNAP, TANF)	Generally excluded

The $15,000 ceiling and the $50 minimum

Oklahoma's guideline table caps at a combined gross monthly income of $15,000. For combined incomes above that ceiling, a judge has discretion to add an amount on top of the table figure for $15,000, based on the child's needs and the family's circumstances, rather than reading a number straight off the table. At the other end of the scale, Oklahoma sets a minimum monthly obligation of $50, which applies even at the lowest combined income levels on the schedule. Oklahoma does not use a separate self-support reserve mechanism the way some states do — low-income cases are handled directly through the low end of the guideline table itself.

Worked example — the basic calculation

The parenting time adjustment

Oklahoma's parenting time adjustment under 43 O.S. §118E is one of the more mechanical features of its guidelines. A noncustodial parent with at least 121 overnights per 12-month period may qualify for a reduction in their support obligation. The combined base obligation is multiplied by a factor that scales down as overnights increase, and the result — the "adjusted combined child support obligation" — is then split between the parents based on their income shares and the percentage of time the child spends with each of them.

Overnights per year	Multiplying factor
121 to 131 overnights	2.0
132 to 143 overnights	1.75
144 or more overnights	1.5

Health insurance, medical expenses, and child care add-ons

The basic obligation covers everyday costs like housing, food, and clothing. Reasonable and necessary uninsured medical expenses beyond routine care, along with work-related child care costs, are generally added to the base obligation and divided between the parents in proportion to their income share. Health insurance is generally considered reasonable in cost when the premium share for the parent providing coverage does not exceed 5% of that parent's gross monthly income. Oklahoma also uses a separate cash medical support table for lower-income cases where a child isn't covered by health insurance.

For a broader look at how property and spousal support are handled alongside child support, see the Oklahoma divorce finances overview. We also have a companion guide on how alimony is calculated in Oklahoma, where courts weigh need and ability to pay without a statutory list of factors.

When can Oklahoma child support be modified?

Either parent can ask a court to modify an existing order under 43 O.S. §118I when there has been a material change in circumstances. Oklahoma generally treats a recalculated obligation that would differ from the current order by 20% or more, and by at least $30, as a material change — though a change in parenting time or a child's costs can also trigger a review. Informally reducing or skipping payments without a modified order is not a safe substitute for going back to court, since the original order generally stays enforceable until it's formally changed. For more on how the modification process typically works, see our general guide on child support modification.

Common questions about Oklahoma child support

How is child support calculated in Oklahoma? Oklahoma combines both parents' adjusted gross monthly incomes, looks up the combined obligation on the state's Schedule of Basic Child Support Obligations, splits it based on each parent's income share, and then adds health insurance and work-related child care costs divided the same way. For a broader explanation of income shares versus other state models, see our general guide on how child support is calculated.

What counts as income under Oklahoma's guidelines? Wages, self-employment income, retirement and Social Security benefits, rental income, and most other recurring income generally count under 43 O.S. §118B. Means-tested public assistance is generally excluded, and a court can impute income to a parent who is voluntarily unemployed or underemployed.

How does the parenting time adjustment work in Oklahoma? A noncustodial parent with 121 or more overnights a year may qualify for a reduction under 43 O.S. §118E, using a multiplying factor that scales down from 2.0 to 1.5 as overnights increase. The adjustment can't push support above what would otherwise be owed, and it stops applying once a parent has more than 205 overnights.

Can Oklahoma child support be modified? Yes, when there's a material change in circumstances — generally a recalculated amount that differs from the current order by 20% or more and at least $30. The change generally needs to go through the court to be enforceable.