How Child Support in Illinois is Calculated

Though child support decisions come during an emotionally fraught time for parents, it’s important to remember that such court orders are not punitive. Rather, they are created in the best interest of the children they stand to benefit. For this reason, legal orders for parents to pay child support are not made in an arbitrary way or based on anyone’s opinion. Rather, guidelines governing these important decisions are written into Illinois law and are applied the same way in most cases.

Every family is different, but the legal guidelines account for this by providing a mathematical formula to calculate the appropriate support amount rendering equal application of the law. While in general the guideline will be applied, there are instances and circumstances when a Judge can deviate from the guidelines to consider a unique situation.

How Child Support is Decided in Illinois?

Illinois law uses a system called the income shares method to calculate the appropriate amount of support that one parent may pay to another for the benefit of their mutual child.

Enacted in 2017, the income shares method replaced a “straight percentage” based formula, thus providing a more nuanced way to determine the most equitable child support order. This formula takes into account both parents’ incomes, the number of children, the shares of parenting time, and the cost of living. This series of calculations provide family court judges with a standardized way to apply the law.

While the custodial parent — the one who spends the majority of parenting time — often receives child support payments, that is not always the case. Ultimately, the income shares formula decides how the balance of payments falls.

Who is Responsible for Paying Child Support in Illinois?

Every legal parent is responsible for the financial support of their minor child, according to Illinois law. Not even the other parent “waiving their right” to child support can remove this legal obligation. Each parent has an obligation to contribute financially to their child’s health, education, well-being, and standard of living.

This includes:

  • Legally married parents who are divorcing
  • Unmarried parents who are separating
  • Parents who legally adopted children
  • Child support when parents share allocation of parental responsibility (often referred to as custody)

Even when parents have a 50/50 allocation agreement, Illinois law may require one parent to pay child support. Depending upon the parents’ individual incomes and the child’s needs, a family court judge may determine that one parent must pay child support to compensate for an imbalance.

How Much is Child Support in Illinois?

Figuring out how much child support is in Illinois is a complex process, so it’s important to consult with a legal professional. However, you can get an idea of how much you may have to pay by using the Illinois Department of Healthcare and Family Services Child Support Estimator. This tool walks users through several questions to provide an approximation of their case’s child support obligations.

Factors that may affect child support calculations:

One or both parents pays or receives maintenance or spousal support (alimony) from one another, or other parties.

The child in question receives Social Security benefits on behalf of a retired or disabled parent.

One parent pays for the child’s health care, childcare or extraordinary expenses.

One or both parents pay child support for other children.

One or both parents legally support other children.

What is child support used for?

Child support payments are meant to cover a child’s core expenses, including the basics of living such as reliable shelter, nutritious food, and well-fitting clothing suitable for conditions.

Child support also is allocated for education expenses, health insurance and costs, and basic transportation expenses.

To determine how parents will share expenses that extend beyond the basics, they must make an additional personal or legal agreement that lays out these terms.

Do you have Illinois child support questions?

The legal team at Sterk Family Law Group will help you understand how Illinois child support law relates to your individual situation. Call us to set up a free, no-obligation consultation at (815) 600-8950 or complete the form below:


This is a legal advertisement from Sterk Family Law Group. It does not constitute legal advice and should not be construed as such. This article is for informational and educational purposes only.

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