Illinois · Checked October 23, 2026
Illinois child support calculator
Illinois works out child support with the income shares model. Here is what that means, what to gather and where to run the state's own calculator.
Open the official Illinois calculator
How Illinois calculates child support
Both parents' incomes are added together, the state's schedule gives the support a child would get if the parents lived together at that combined income, and each parent pays their share in proportion to their income. Most income shares states then adjust for health insurance, child care and, often, parenting time.
Use the official Illinois calculator
Illinois's schedule and adjustments are long and change when the state reviews its guidelines, so the most reliable estimate comes from the state's own tool: Illinois HFS: child support estimator.
What you will need
- Both parents' gross monthly income.
- The number of children in the case and any other children either parent supports.
- Monthly cost of the children's health insurance and work-related child care.
- The parenting-time schedule (overnights per year).
Frequently asked questions
How is child support calculated in Illinois?
Illinois uses the income shares model. Both parents' incomes are added together, the state's schedule gives the support a child would get if the parents lived together at that combined income, and each parent pays their share in proportion to their income.
Is there an official Illinois child support calculator?
Yes. The state provides one: Illinois HFS: child support estimator.
Other states: child support calculator by state · Guides: child custody · divorce
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General information from Illinois's guidelines and official sources, checked October 23, 2026. A judge can order a different amount; this is not legal advice. AmericanAttorneys.net is not a law firm.