Missouri uses a formula based on both parents' income
Missouri calculates child support by taking a percentage of the combined income of both parents, then dividing that amount between them based on how much each parent earns. The state does not use a flat dollar amount — what you owe or receive depends on how much money both parents make and how many children need support.
The percentage itself is set by law and increases with each additional child. For one child, the percentage is 20 percent of combined parental income. For two children, it is 25 percent. For three children, 32 percent. For four children, 40 percent. For five or more children, the court can order more than 50 percent if it determines that amount is necessary.
Once the court calculates the total support obligation, it divides that obligation between the parents in proportion to their incomes. If one parent earns 60 percent of the combined income and the other earns 40 percent, the parent earning 60 percent pays 60 percent of the total obligation.
Key Takeaways
- Missouri child support is calculated as a percentage of both parents' combined income, ranging from 20 percent for one child to 40 percent or more for four or more children.
- The court divides the total obligation between parents based on their individual income — the parent earning more pays a larger share.
- Income includes wages, salary, self-employment earnings, bonuses, and certain benefits, but the court can exclude or adjust income in specific circumstances.
- The amount can be modified if either parent's income changes significantly or if custody arrangements change.
- A family law attorney or your local family court can provide a calculation based on your specific income figures.
What counts as income for child support purposes
The court includes most forms of money you receive when calculating child support. This includes W-2 wages from employment, self-employment income, bonuses, commissions, overtime pay, and rental income. It also includes unemployment benefits, workers' compensation, Social Security benefits, and military allowances.
The court does not automatically include child support or spousal support you receive from another relationship, though it may consider it in certain cases. Means-tested benefits like SNAP or Medicaid do not count as income. Gifts and inheritances are generally not counted unless they are regular and recurring.
If you are self-employed or your income varies, the court typically averages your income over the past two years. If you recently changed jobs or had a significant income change, bring documentation of both your old and new income to show the court the actual shift.
How the court handles income below the minimum wage or above the cap
Missouri law sets a parental income cap for the percentage calculation. As of 2024, that cap is $30,000 per month in combined parental income. If both parents together earn more than $30,000 per month, the court calculates support on the first $30,000 and then uses discretion to order additional support based on the children's needs and the parents' ability to pay.
If a parent's income is very low or zero, the court does not automatically order zero support. Instead, it may impute income — assign an income level based on the parent's work history, education, or earning capacity. A parent who quit a job to avoid support, for example, may be assigned income at the level of their previous job.
The court can also adjust the calculated amount if it finds that the standard percentage would be unjust or inappropriate given the specific circumstances — for instance, if one parent has significant debt, high medical expenses, or other children from a different relationship.
Other factors the court considers beyond the formula
The percentage formula is the starting point, but Missouri law allows the court to adjust the amount based on other factors. These include the cost of health insurance for the children, whether one parent pays for childcare so the other can work, and the amount of time each parent spends with the children.
If one parent has custody most of the time and the other has visitation, the support obligation may be different than if custody is split equally. The court also considers whether either parent is supporting other children from a previous relationship, and whether there are significant differences in the parents' standard of living or earning potential.
Tax benefits matter too. The court may account for the federal child tax credit and dependent exemptions when setting the final amount, since these reduce the actual cost to the parent receiving support.
How to get a child support calculation for your situation
You can request a child support calculation through the family court in the county where the child lives or where the other parent lives. You will need to file a petition or motion for child support, along with financial documents showing both parents' income. The court will then schedule a hearing where both parents can present their income information.
Missouri's Family Support Division can also help establish or modify child support orders. If you receive TANF (Temporary Assistance for Needy Families) or SNAP, the state may pursue child support on your behalf as part of the program. You can contact your local Family Support Division office to learn whether they are already involved in your case.
If you and the other parent agree on an amount, you can submit a written agreement to the court for approval. The judge will review it to make sure it meets the state's guidelines and is in the children's best interest. An agreed amount does not have to follow the formula exactly, but the court must find it reasonable.
When and how child support amounts change
A child support order remains in effect until the child turns 18, graduates from high school (whichever is later), or reaches age 21 if the child is still in high school. The amount can be modified before that date if there is a substantial change in circumstances — typically defined as a 10 percent or more change in either parent's income.
Either parent can file a motion to modify support if they lose a job, receive a significant raise, or if custody changes. The court will recalculate based on current income and may increase or decrease the amount. If you do not file to modify and simply stop paying, you will accumulate arrears (back support owed), which can result in wage garnishment, tax refund interception, or other enforcement action.
Missouri also allows for automatic review of child support orders every three years if neither parent requests it sooner. This review looks at whether income has changed enough to warrant an adjustment.
Frequently Asked Questions
Does Missouri have a minimum child support amount?
Missouri does not set a flat minimum, but the court will not order less than $50 per month unless it finds that amount would be unjust. In practice, most orders are significantly higher because they are based on the percentage formula applied to actual income.
What if one parent is unemployed or underemployed?
The court may impute income based on the parent's education, work history, and earning capacity. A parent who is intentionally working below their ability to avoid support may be assigned income at a higher level. If a parent is genuinely unable to work due to disability or age, the court can consider that when setting the amount.
Can child support be modified if my income goes down?
Yes, but only if the change is substantial — usually 10 percent or more of your current income. You must file a motion to modify with the court and provide documentation of the income change. Support does not automatically decrease; you have to request the modification.
Does the amount change if custody changes?
Yes. If the custody arrangement shifts — for example, from one parent having primary custody to a 50/50 split — the support obligation recalculates based on the new arrangement and each parent's income. The parent who now spends more time with the children may owe less or receive more support.
What happens if I cannot afford the amount ordered?
Contact the court or the Family Support Division immediately and request a modification hearing. Explain your financial situation and provide documentation of your current income and expenses. Do not simply stop paying, as this creates arrears and can lead to enforcement action including wage garnishment or license suspension.