How the income shares model works
Child support in the United States is set by state guidelines, not by federal law. Most states use the income shares model: both parents' incomes are combined, a basic support obligation is read from the state's schedule for that combined income and number of children, and each parent is charged a share of it in proportion to their income. A minority of states use a percentage-of-income model that looks only at the paying parent.
Enter both monthly incomes, the basic obligation your state schedule gives for your combined income and child count, and the monthly add-ons for health coverage and work-related child care. The tool returns the combined income, the noncustodial parent's percentage share and the monthly and annual estimate.
Basis: states must maintain numeric child support guidelines and review them at least every four years under 42 U.S.C. 667 and 45 C.F.R. 302.56; the schedules themselves are state law. Amounts and add-on rules as of September 2026 differ by state, and parenting-time credits, self-support reserves and high-income caps can change the result. Check your state guideline worksheet.
This calculator is for reference only and is not legal advice. Courts may deviate from the guideline figure when the facts justify it. Consult a licensed family law attorney about your specific situation.
Frequently Asked Questions
Each state publishes a schedule of basic child support obligations, usually as an appendix to its guideline rules or as an official online worksheet. You read the amount for your combined monthly income and the number of children.
In many states yes. Once the paying parent exceeds a threshold number of overnights, the guideline applies a shared-parenting adjustment. The threshold and the formula vary widely, so check your state worksheet.