Child Support in St. Louis City County, Missouri: How Much Will You Owe?

Quick answer: it depends on both parents' incomes, how many children you have, and the parenting schedule. The calculator on this page turns those numbers into a real guideline estimate in about a minute. It is an educational estimate, not legal advice, and the judge always sets the final amount. FamilyCourtHelp.com is a self-help resource, not a law firm.

If you are facing a child support case in St. Louis City County, Missouri, the first question is almost always the same: how much? The honest answer is that it depends on income, children, and parenting time, all run through Missouri's statewide formula. Below you can see how that formula works and try it with your own numbers.

Missouri follows the Income Shares model under Missouri Supreme Court Rule 88.01 (Form 14). The court combines both parents' monthly gross incomes, looks up the basic support obligation on the state's guideline schedule for that income level and number of children, then prorates the obligation between the parents according to each parent's percentage share of the combined income.

What counts as income? Missouri runs the formula on gross income, meaning income before taxes come out. Gross income from any source. Self-employment income is net of reasonable business expenses.

Parenting time matters directly in Missouri: the number of overnights each parent has changes the math itself. Missouri uses a shared-care formula, so the time the children spend with each parent can change the final number. Form 14 includes a line that adjusts the support obligation for overnight visitation and custody, recognizing that the parent who has the children overnight also covers direct costs during that time. More overnights with the paying parent generally reduces the calculated amount, while the basic obligation still starts from both parents' combined gross income. The on-page calculator gives an estimate only, and the actual Form 14 figure controls.

When does it end? Missouri child support generally ends at age 18 but extends up to age 21 if the child is enrolled in higher education and meets the academic and notification requirements of § 452.340.

Can the amount change later? File a motion to modify in circuit court or request review through Family Support Division. A 20% variance or substantial and continuing change supports modification.

If payments fall behind, Missouri has real enforcement tools. Missouri FSD enforces through immediate income withholding, tax intercept, license suspension, lien filings, credit reporting, and contempt referrals.

Child support cases arising in St. Louis City County are generally handled through Missouri's Circuit Court, and Missouri Family Support Division (Department of Social Services) runs the state's child support services program. Offices, forms, and local practice can vary from county to county, so confirm the current details with your local court or the agency. This page stays general on purpose and does not give St. Louis City county filing steps.

The calculator on this page is the same live engine behind our full Child Support Calculator. Enter both incomes, the number of children, and the overnight split, and the estimate updates instantly. The full calculator page adds extras like health insurance, child care costs, and saved scenarios.

Bottom line for St. Louis City County, Missouri: the guideline number comes from incomes, children, and parenting time. Run the estimate on this page, keep your paperwork honest and complete, and let the court confirm the final amount.

Frequently asked questions

How much child support will I owe in St. Louis City County, Missouri?

There is no flat amount. Missouri uses the Income Shares model under Mo. Sup. Ct. Rule 88.01 / Form 14, so the number depends on both parents' incomes, the number of children, and the parenting schedule. The calculator on this page gives you a guideline estimate in about a minute, and the court sets the final amount.

Does parenting time change child support in Missouri?

Parenting time matters directly in Missouri: the number of overnights each parent has changes the math itself. Keep a clear record of your actual schedule, because the overnight count is one of the main inputs.

When does child support end in Missouri?

Age 18, or up to age 21 if the child is enrolled in higher education and meets the requirements of Mo. Rev. Stat. § 452.340.

Can the child support amount be changed later in Missouri?

Usually yes, when circumstances change enough. A 20% change between the existing order and a new Form 14 calculation, or any substantial and continuing change.

Who handles child support cases in St. Louis City County?

Cases are generally heard in Missouri's Circuit Court, and Missouri Family Support Division (Department of Social Services) handles services like locating parents, establishing orders, and collecting payments. Confirm the right office with your local St. Louis City county court.

Is the calculator on this page the official Missouri calculator?

No. It is a free educational estimate built on Missouri's guideline model. Missouri Family Support Division (Department of Social Services) publishes the official rules and worksheets, and the judge always sets the final amount. Most parents use the estimate to budget, sanity-check a proposal, or decide whether to ask for a change.