Unlike many other states, Missouri does not provide an official online calculator for child support. But the state does provide a fillable PDF Child Support Amount Calculation Worksheet, commonly called "Form 14," that you can use to calculate your basic support obligation based on the current Missouri child support guidelines. You can download a fillable PDF of Form 14, as well as the complete directions and the current schedule of basic child support obligations, from the Missouri Courts Child Support Forms page.
You'll need to have some basic information on hand before doing the calculations, including both parents' income, certain expenses for the child (including health insurance coverage and work-related child care), and either parent's existing support obligation for other children (such as kids from a previous relationship).
Before you fill out the worksheet, you should also know what your physical custody (parenting time) arrangements will be. The parent who doesn't have the children most of the time typically pays child support to the primary custodial parent, but the guidelines allow an adjustment for some expenses during the noncustodial parent's overnight visitation. If you're still negotiating custody, you might try multiple calculations under different scenarios.
The worksheet directions include details on what counts as income and which adjustments to income are allowed, as well as the special rules when the parents have their children for about the same amount of time or when they have split custody (meaning that each will have at least one of their children most of the time).
Missouri presumes that the amount calculated under the guidelines is appropriate, but you may argue that a different amount would be better in your situation. Whether you and the child's other parent have agreed on a support amount that departs from the guideline or a judge decides for you, the judge will have to find that using the amount calculated under the guidelines would be unjust or inappropriate, and that a different amount would be in the child's best interests. (Mo. Rev. Stat. § 452.340 (2024).)
Learn more about how child support works in Missouri, including factors judges must consider when deviating from the guidelines.
Typically, you'll apply for child support as part of the process of filing for divorce in Missouri. You'll include your completed child support worksheets along with the other divorce papers.
If you aren't married to your child's other parent, you may get help with requesting support by applying for child support services from the Family Support Division (FSD) in the Missouri Department of Social Services. If needed, the FSD may also help with establishing the child's legal paternity or parentage and locating absent parents.
If you're having trouble collecting support payments, the Missouri FSD can also help enforce court-ordered child support. Depending on how much the other parent owes, the agency has several ways of enforcing child support, including withholding support from paychecks, reporting the debt to credit bureaus, intercepting income tax refunds, intercepting workers' compensation or unemployment benefits, seizing money from bank accounts, placing liens on property (so the delinquent parent can't sell it or borrow money before paying off the debt), and suspending the parent's driver's or other licenses.
Either parent may request a modification in the amount of child support in Missouri. Generally, you'll need to demonstrate that there has been a significant change in circumstances that's ongoing and is so significant that the current amount of support is unreasonable. However, the judge will conclude that you've met that requirement if a new calculation (with the current guidelines and your current financial circumstances) results in a support amount that's at least 20% different than the existing amount (as long as the existing amount was based on a standard calculation rather than a deviation from the guideline). (Mo. Rev. Stat. § 452.370 (2024).)
You may request a review of your current child support order from the Missouri FSD every three years. If it's been less than three years since the order was issued, reviewed, or modified, the agency will review your order only if there are special circumstances in your case. If a review shows that a modification would be warranted, the FSD may file a motion in court for a modification.
You also have the option of filing a modification request directly with the court. But without FSD assistance, you should consider speaking with a family lawyer.