Can I Modify a Child Support Order in Illinois?

 Posted on October 03, 2026 in Child Support

Child support orders in Illinois can be updated after they’ve been issued. Whether an order qualifies for modification depends on the reasons the parent or parents have for changing it. In some cases, the amount of time that has passed since the last change can also be relevant.

A Kane County, IL child support attorney can help you find out whether your situation may qualify for a modification in 2026.

When Can a Child Support Order Be Modified in Illinois?

Under 750 ILCS 5/510, an Illinois child support order can be changed in several situations. One is when there has been a substantial change in circumstances since the order was entered or last modified.

A modification may also be available in certain HFS cases when the current amount differs from the guideline amount by at least 20 percent and at least $10 per month, and at least 36 months have passed since the order was entered or last changed. This rule may not apply if the existing order intentionally departed from the guidelines and the reason for that departure has not changed.

A court can also modify support when the child needs health care coverage that the current order does not provide.

A new option takes effect on January 1, 2027. Under Public Act 104-733, a parent who will be incarcerated for more than 180 consecutive days may have support reduced to $0. If the required notice of incarceration is filed and no written objection is filed within 45 days, the reduction takes effect by operation of law. After the parent has been released for 90 days, support is recalculated under the new statutory rules unless another modification is requested.

What Counts as a Substantial Change in Circumstances in Illinois?

There is no set legal definition for a "substantial change in circumstances." Judges decide what qualifies based on the facts of each family’s situation. A major loss or increase in either parent’s income is the most common example.

Other changes that may qualify include:

• A new disability or serious illness
• A large jump in the child’s medical, school, or child care costs
• A change in the parenting time schedule.

Modification works in both directions. A parent paying support may ask for a decrease after a significant drop in income. A parent receiving support may ask for an increase if the other parent’s income or the child’s needs have increased. The other parent can’t block a modification by arguing the change was foreseeable unless the order or written agreement says a specific future event doesn’t count as a substantial change.

Can You Get Reduced Child Support if You Quit Your Job in Illinois?

Quitting your job does not necessarily prevent you from getting a child support modification. The court will look at why you left and whether the change in income is legitimate.

If a judge finds you are voluntarily unemployed or underemployed, support can be based on your potential income instead of what you actually earn (750 ILCS 5/505(a)(3.2a)). The court may look at your work history, job skills, education, health, and record of seeking work.

Even if you are involuntarily laid off, you may want to keep records of your job applications to show you are actively trying to be employed again.

Is an Illinois Child Support Modification Retroactive?

A modification typically only affects payments that come due after you file your motion and give the other parent proper notice. It doesn’t go back to the date your income changed.

You also can’t lower your payments on your own while you wait. Until a judge signs a new order, the existing one is enforceable, and missed payments are considered a debt you owe.

How Do You Request a Child Support Modification in Illinois?

The process usually starts with a petition to modify filed in the court that entered your original order. Both parents show updated financial information, such as pay stubs, tax returns, and financial affidavits. The court then runs the new numbers through the Illinois income shares guidelines to determine the new support amount. If there’s a hearing, the parent asking for the change must present evidence about why the change is needed.

If both parents agree on a new amount, they can submit an agreed order. The judge still has to approve it, and may ask follow-up questions if it departs from the state guideline amounts.

Parents with an open HFS case may also be able to request a review through the department at no charge. HFS can’t address parenting time or parental responsibilities, though. If those issues are part of the change, the court is often the better place to start.

Call a St. Charles, IL Family Law Attorney Today

A child support order that worked a few years ago may not fit your family now. Our Kane County, IL child support lawyers can review your current order and what’s changed since it was entered so you can present your case effectively.

Our main attorney is a trained mediator with significant family law experience. We focus on solving disputes out of court when possible, but we’re prepared to litigate aggressively when a case requires.

Call Shaw Sanders, P.C. at 630-584-5550 to schedule your free consultation.