Calculating Child Support in Illinois

  • Robert S. Thomas,
  •   Family Law
  •   Comments Off on Calculating Child Support in Illinois


State law in Illinois requires that both parents financially support their children. The underlying theory supporting this is that children should not suffer simply because their parents are no longer together. If you are in the process of a divorce or child custody dispute, you should consult with a family law attorney for assistance. The reason for this is because the child support laws in Illinois have recently undergone some dramatic changes.

Child Support Based on Guidelines

Traditionally, Illinois has calculated the child support obligation of a non-custodial parent by taking that parent’s net income, then multiplying that by a fixed percentage set forth in statutory guidelines. If a non-custodial parent was responsible for one child, they would be ordered to pay 20% of their net income in child support. Two children would be 28%, three children 32%, four children 40%, five children 45%, and six or more children would be 50% of the non-custodial parent’s net income. This calculation did not really account for how much time the children actually spent in the non-custodial parent’s care. In fact, the court could only stray from the guideline percentages upon a finding that the guideline child support would not meet the children’s best interest.

New Child Support Law

In 2016, the Illinois legislature passed a dramatically different method of calculating child support obligations, which was signed by the Governor. Scheduled to take effect on July 1, 2017, Public Act 99-0764 replaces the prior guidelines with an “income shared” approach. The income shared model is the most common model in the country. The calculation begins with the scenario of an intact family and looks at the combined income of the household and the number of children, then calculates “the amount that parents who reside together expend for the needs of their child or children.” The model then calculates a pro-rated child support obligation that each separated parent must pay. The new guidelines and worksheets can be found at the Illinois Healthcare and Family Services website.

How is the income shared model different from the old fixed percentage guidelines? It takes into heavy consideration the income of both parents, as well as the reality of how much time each parent cares for the child. Many states have determined that this is a more fair and realistic approach to the actual costs of financially supporting a child. However, the new legislation is not without its caveats. First, it does not fully account for “shared parenting” adjustments, in which parents both have relatively equal time with the child (146 overnights or more per year). Second, the new legislation applies to child support obligations ordered after July 1, 2017, and the new law does not entitle parents currently under a child support to seek a modification.

Contact the Law Offices of Robert S. Thomas today if you are in the process of a divorce or child custody dispute. The recent changes in child support in Illinois can be confusing and complex, but we can help guide you with clarity and purpose. For more than twenty years, I have represented clients in family law disputes. Call my office today at 847-392-5893 to schedule an appointment or visit our website.

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