How Illinois child support is determined

February 24, 2022

Illinois child support is determined pursuant to law, 750 ILCS 5/505. Child support is based on several factors: the number of children, the parenting time split, and both parents’ incomes. The state provides an online calculator to help you estimate your potential obligation or payment


The calculator starts by asking for your gross monthly income and your co-parent’s. It then factors in overnight stays for each parent and the cost of health insurance for the child. Note that it uses “net income” (a specific legal calculation) rather than your paycheck amount. If you get paid every other week, take your gross income and multiply it by 26 and divide by 12 to get to a monthly amount.

The calculator makes certain assumptions, like the parent with majority time claims the child as a dependent and that your tax withholding is accurate.

Can parents set their own Illinois child support amount?

Sometimes. While the court always has the final say, some flexibility exists. The court’s primary goal is to ensure the child’s financial needs are met. If the calculator suggests $900/month but you agree on $750 with other expenses covered, the court will likely approve. However, a drastically reduced amount like $200 would probably be rejected.

Will I pay Illinois child support if we share 50/50 time?

Maybe. Illinois child support can be required, as clarified in the Illinois Supreme Court case In re Marriage of Turk. The goal is to provide for the child in both households. The newer Illinois child support laws even account for equal parenting time scenarios. Think, if one parent makes $450,000 a year and the other parent makes $55,000 a year, is it fair to make the higher-earning parent pay child support? The answer is yes, it is, because Illinois child support is supposed to support a child — and the child deserves to have access to necessities in both homes. It would actually be hard on a child to transition from a home with plenty to a home with little.

Need specific advice about Illinois Child Support?

Illinois Child support calculations have unique wrinkles. As an experienced family law professional, I can guide you through these complexities. I’ve helped clients with Illinois child support for over 17 years.

Ready to resolve your child support issue?

If child support is the last hurdle toward finalizing your agreement, use the state’s calculator as a starting point. Once you have a potential amount settled, I can help with the legal paperwork and finalize the agreement in court. Simply reach out when you’re ready to take the next step.


If you can settle this, as well as the other issues, such as time with your child, holidays, and how you will pay for your child’s needs, I would be happy to help you get these agreements into Court orders – all you have to do is reach out when you are ready.


This article is for informational purposes only and should not be taken as legal advice. Every situation is different and you should hire an attorney to answer questions about your specific case.