Missouri Child Support Calculator

How Missouri Calculates Child Support

Missouri determines child support using the Income Shares Model, the standard set out in Mo. R. Civ. P. 88.01 / Form 14. Under this model, the incomes of both parents are combined to estimate what they would have spent on the children if the family were intact, and that total obligation is then divided between them in proportion to each parent's share of the combined income.

The calculator above applies that formula to the income and expense figures you enter and shows each step of the math, so you can see exactly how the estimate is built. Because every order ultimately runs through a judge, the guideline figure is a starting point rather than a guaranteed result — the sections below explain what goes into it and where real orders can differ.

Key Rules Behind the Missouri Formula

• Missouri uses the Income Shares model under Mo. R. Civ. P. 88.01, with the calculation performed on Form 14 (the Missouri Child Support Amount Calculation Worksheet).
• Form 14 runs on GROSS income: Line 1 is one-twelfth of each parent's yearly gross income, and taxes are never deducted anywhere on the worksheet. The only adjustments are court-ordered maintenance received or paid, other court-ordered child support, and support for other children in the parent's primary custody.
• The basic obligation comes from the Schedule of Basic Child Support Obligations and is prorated between parents based on each parent's share of combined adjusted monthly gross income. This calculator uses the updated schedule adopted by Supreme Court order of March 4, 2025, effective January 1, 2026.
• Missouri uses a specific overnight credit formula — when the noncustodial parent has 111 or more court-ordered overnights per year (approximately 30% of the time), a credit is applied to reduce the support obligation.
• Health insurance premiums, work-related childcare costs, and uninsured extraordinary medical expenses are added to the basic obligation and divided proportionally between parents.
• Form 14 creates a rebuttable presumption of the correct child support amount — courts may deviate upon a written finding that application would be unjust or inappropriate (Mo. R. Civ. P. 88.01(e)).
• Missouri requires both parents to provide health insurance for the children if available at a reasonable cost through an employer or group plan.

What Counts as Income

Child support guidelines are built on each parent's income, so the figure you enter matters more than any other input. Most states start from a broad definition of gross income that includes wages, salary, tips, commissions, bonuses, self-employment earnings, and many forms of government benefits, then subtract specific deductions to reach the income the formula actually uses.

Missouri's rules under Mo. R. Civ. P. 88.01 / Form 14 spell out which deductions apply and whether the formula runs on gross or net income. The calculator's field labels tell you which figure to enter; when in doubt, use your most recent pay stubs and tax return, and confirm the details in the Missouri child support laws guide.

How to Establish a Child Support Order in Missouri

A child support obligation becomes enforceable only once a court or the state child support agency issues an order. Either parent can request one, and in Missouri, as in every state, the local child support agency that operates under the federal Title IV-D program can open a case, locate the other parent, establish paternity if needed, and ask the court to set support using the guideline formula.

When you apply, expect to provide proof of income for both parents, the child's information, and details about health insurance and childcare costs — the same inputs this calculator uses. Running your numbers here first gives you a realistic idea of the order amount before you file.