How it works · official guideline
How child support is calculated in Missouri
Missouri law requires the Missouri Supreme Court to keep a rule with numeric child support guidelines (Rule 88.01 and the Form 14 worksheet); the amount they produce is presumed correct unless the court finds in writing that it would be unjust or inappropriate. The guidelines must allow up to a 50% adjustment for joint physical custody or visitation.[1]
Missouri’s model
Not verified yet
No official calculator confirmed yet
Read the guideline: RSMo § 452.340.8–.9The state child support agency or your court clerk can run the official numbers.
Why no calculator here? We publish a calculator only after it reproduces the state’s official numbers exactly. We haven’t matched Missouri’s yet.
From the official text
The rules behind Missouri’s numbers
The guideline is RSMo § 452.340.8–.9. Open each rule to read the exact words.
- Departing from the guideline
Rebuttable presumption; written finding needed to deviate
The guideline amount is presumed correct; the court must make a written or on-the-record finding, naming the specific factors, to depart from it.[1]
Official text · RSMo § 452.340.9
“There shall be a rebuttable presumption, in any judicial or administrative proceeding for the award of child support, that the amount of the award which would result from the application of the guidelines established pursuant to subsection 8 of this section is the correct amount of child support to be awarded.”
- Shared parenting time
Up to 50% below the basic amount for equal or substantially equal time
For joint physical custody where the children spend equal or substantially equal time with both parents, the court may set support up to 50% below the basic guideline amount.[1]
Official text · RSMo § 452.340.11
“The court may award child support in an amount that provides up to a fifty percent adjustment below the basic child support amount authorized by the child support guidelines described under subsection 8 of this section for custody awards of joint physical custody where the child or children spend equal or substantially equal time with both parents.”
- Review cycle
Guidelines reviewed at least every four years
The Supreme Court must review the guideline rule at least once every four years.[1]
Official text · RSMo § 452.340.8
“Any rule made pursuant to this subsection shall be reviewed by the promulgating body not less than once every four years to ensure that its application results in the determination of appropriate child support award amounts.”
Guideline: RSMo § 452.340.8–.9 (Missouri Revisor of Statutes), checked October 26, 2026.
Estimate and general information only — not legal advice. MediationList is a directory, not a law firm, and doesn’t endorse any mediator. Guidelines change; confirm with the state child support agency or your court (sources checked October 26, 2026). See also divorce laws in Missouri and child support in every state.
Sources
Missouri’s child support guideline, rules and official tools, read on the official sites, with the date we checked each.