The question “How can I modify my child support” is one of the most frequently asked questions in family law. Child support is often a hotly contested issue, as many parents feel like they are paying too much, or their ex-partner is paying too little.
But, opinion has little to do with it. Child support is set by Illinois state guidelines, so it is usually just a matter of doing the math based on what each party is earning and how much time they spend with the child under the current law.
That said, there are important deviations, credits, and other nuances that an experienced family law attorney can educate you about, as well as providing you with assistance in navigating your case through the court system expediently and efficiently.
The Recent History of Child Support Law in Illinois
The first thing to know is that in the fall of 2016, the Illinois legislature made a major change to how child support is calculated. Prior to 2016, the state would only look at the income of the parent who exercised less parenting time with the children, i.e. the minority parent.
The state would then assess a child support obligation based on a percentage of their income, such that for one child a parent would pay twenty percent of their income in child support, twenty-eight percent for two children, thirty-two percent for three children, and so on. The law did not consider how much time the children were spending with the minority parent at all.
In the fall of 2016, as part of a sweeping revision to domestic relations law that included getting rid of the term “custody”, the legislature changed the child support calculation model to a shared-income model.
Instead of looking only at the income of the parent with less parenting time, the shared-income model combines their incomes to mimic what their household income would be like had the parents never split up. The result is that both parents are now assessed a child support obligation, but only one parent actually makes payments toward that obligation.
Impact of Overnight Parenting Time
The other major change is that the amount of time a parent spent with their child had an impact on the child support amount, which was not considered before. Now, if the parent exercising less time has over 146 overnights with the child, their child support obligation decreases significantly because they are already providing significant support to the child/children in their home.
It is important to understand that this formula only considers overnights, not days spent with the child, when determining whether a parent is entitled to this deduction.
If you have a child support order from before 2016, it is important to know that the factors and way the support amount is calculated have totally changed and the new law will be applied if either you or your ex-partner seeks to modify child support.
It is critical to consider how those changes could impact your support amount before proceeding with a modification, to your detriment or your advantage. Talking to an experienced family law attorney can help you understand whether a modification could be financially beneficial to you, or not.
Modify Child Support in Illinois
You will first have to get your financial affidavit prepared, and then you can file a motion to motion to modify child support. There has to be a “substantial change in circumstances” which is different depending on which judge you get.
Most time, the passage of time can be enough for a substantial change, especially as your child gets older. In your motion, detail out long it has been since the order was placed and detail the changes in circumstance. Some suggestions would be that the other party now makes more money, or you might be making less money.
Suppose it has been less than thirty days, and you notice the order has a typo. In that case, a modification can be requested immediately to correct the error in the order. After thirty days, the order with the error is binding.
After that time, a child support order can still be modified, only:
- There has been a substantial change in circumstances
- At least three years have passed since the last child support order was put in place.
- The previous order did not address healthcare coverage for the child; or
- A written request for a review is received by the Department of Child Support Services from the custodial parent, non-custodial parent, or another state.
Can My Child Support Be Modified Without Going to Court?
No—you can’t change child support without a court order. If you have a formal child support order, only a judge can modify it. The original amount stays in effect until the court approves a new one.
Even if you lose your job or your income changes, child support doesn’t adjust automatically. You still owe the full amount until a judge signs off on a change.
To modify child support, you must file a Motion to Modify Child Support. The law requires you to show a “substantial change in circumstances.” This could include:
- Losing your job involuntarily
- A drop in salary
- An increase in your child’s needs
- A significant raise in the other parent’s income (but only if your income hasn’t also gone up)
If you quit your job, go back to school, or reduce your hours by choice, the court likely won’t approve a change. The income loss must be out of your control.
Also, changes in the law alone won’t justify a modification. If your order was set before 2016, you still need to show a real change in circumstances—just referencing the legal update isn’t enough.
In the end, the judge decides whether your situation qualifies. Both parents must share updated financial information, and the court calculates a new amount based on that. Without a big shift in finances, a judge may not grant a change.
Visit our Chicago Support Modification Lawyers services page to learn more
How Long Does It Take to Modify Child Support?
Understanding the Modification Process
Modifying child support isn’t usually difficult. The court bases the support amount on income and parenting time. One parent begins the process by filing a motion to change the support amount. After that, both parents must exchange financial affidavits. They also provide documentation verifying their incomes over the past two years.
Calculating the New Support Amount
Once they exchange financial information, they calculate the new child support amount. The calculation uses both incomes and the child’s overnight stays with each parent. The formula follows state guidelines and aims to ensure fairness. The court uses these figures to determine the basic support amount.
Requesting Deviations from the Guidelines
Parents can request a different amount if their situation justifies it. For example, if one parent travels long distances to see the child, they may pay less support. If the child has special needs, the other parent may receive additional support. These deviations are not automatic. The judge considers each request individually and uses discretion when deciding.
Issuing the New Support Order
After calculating the correct amount, the judge issues a Uniform Order for Support. Often, both parents agree on this amount because it’s based on fixed guidelines. This agreement helps streamline the process. In most cases, the court finalizes the order within six months.
What Can Delay the Process
Several factors can slow down the modification timeline. If a parent refuses to share complete financial information, the process stalls. Inaccurate affidavits also cause delays and create more legal steps. Busy court schedules can make it difficult to get an early hearing date. These issues may extend the process beyond a year.
Should I Hire a Lawyer to Modify Child Support?
The simple answer is yes. Although modifying child support isn’t a particularly complex process, hiring an experienced and knowledgeable child support lawyer works strongly in your favor. A skilled child support attorney understands how the court calculates child support and can advise you on legal options to reduce your payment amount.
For example, if you provide health insurance for your child, the court may lower your support obligation since you’re already covering that benefit. Similarly, if you have other children from separate relationships, you may also qualify for a reduced amount of support.
Why Legal Help Makes a Big Difference
Most importantly, when you file a motion to modify support, the law allows you to receive relief retroactively from the filing date. If the court grants your request to lower the child support amount, you become entitled to repayment—or a credit—for the difference between the previous and revised amounts from the date you filed.
Even though the law allows retroactive relief, you must specifically ask for it and include it in the new child support order. If you miss this step, you forfeit the benefit. Parents who represent themselves often don’t know they qualify for such credits and might overlook critical legal relief they’re entitled to receive.
An attorney can move your case forward efficiently by tracking deadlines and, if necessary, urging the court to enforce timelines. This helps avoid unnecessary delays. Additionally, if both parents agree, you can modify child support by mutual consent without attending a court hearing. A good attorney can help you negotiate this agreement and save both time and legal costs.
A lawyer also ensures the court correctly calculates the support and completes the paperwork accurately. Even small clerical errors—like checking the wrong box—could result in a biweekly instead of monthly payment obligation.
Fixing such a mistake would require another trip to court. Hiring a family law attorney who understands both the legal and mathematical aspects of child support helps ensure your modification request is handled properly the first time.
Ready to Modify Child Support in Chicago?
Schedule a consultation with one of our Chicago family law attorneys to see how our skilled legal team can help you modify child support or any other family law and divorce-related matters.
FAQs Related to Child Support Modification in Illinois
What is Considered a Substantial Change for Child Support Modification?
A substantial change is not fully defined by law. Still, several cases in Illinois have illuminated what does and does not count as a substantial change. One common example of a substantial change is a change in employment status. Another might be an illness that is keeping you from working. Each of these changes can be considered a substantial change in circumstance.
How Long Ago Must the Substantial Change Be?
All that matters is whether the change is substantial. If you received an order last month and today you learn that your job has been eliminated, then you have a substantial change. If you don’t file for the modification when you lose your job, you will owe the court-ordered amount, even though you are not working.
Always file a motion to let the judge know about your change in circumstance. Once the child support is due, the money is owed to the other person whether you can afford it or not. Always be mindful that you have to follow the court’s order until it is changed.
How Far Back Can I Request Child Support?
Typically, the courts will modify child support from the date you file your petition. But under the Parentage Act, there is a statute that allows you to go back to the day the child was born. There are five requirements to meet under the statute to obtain child support back that far, so call us to see if your circumstances qualify for that type of child support.
I am no Longer Working. Is that a Substantial Change?
It depends on the reason why you are no longer working. Whether the change was voluntary or involuntary can make a difference in your case.
If the change was involuntary, such as your employer decided to reduce his workforce, or your job was eliminated in some way, you are more likely to be able to modify your support amount.
Sickness can also be considered a substantial change, if it affects your ability to earn an income. Sickness might also be a substantial change if the sickness requires expensive medical care.
If the change in employment is voluntary, and you quit your job, or you were fired because of some criminal activity, you may not be able to modify your support. The court will make a finding as to whether your substantial change is allowable depending on the circumstances in your case.
I Got Promoted. Is that a Substantial Change?
Promotions can be a substantial change in circumstances. Financial gains can affect child support in many different ways. For example, if the paying parent has an economic improvement, the support obligation will likely increase. Conversely, the award will likely decrease if the receiving parent has a financial gain.
I Am Now the Custodial Parent. Can I Modify Child Support?
Yes. One factor in the child support calculation concerns the division of parenting time. So, if the division changes, a modification is possible.
My Child is Sick/Disabled. Can I Request a Modification?
If the child has needs that have changed, and the guideline support award is not sufficient to meet those needs, then a deviation from guidelines can be granted. Deviations to child support can be an upward modification or be modified downward depending on the facts in your case.
I Remarried and Had a New Child. Do I Still Have to Pay the Same Amount in Child Support?
Having another child is often not enough to modify the child support award. However, the court will consider new financial responsibilities when reviewing the awards. There might be a substantial change if there is a high need for a new child or family, and you might ask the court to deviate your child support amount.
My Child Is Eighteen Years Old. I No Longer Have to Pay Child Support, Right?
You must pay child support until your child turns 18 or graduates from high school, whichever comes later. If your child becomes an adult but is still in school, child support may still be required.
If you owe arrears when your child emancipates, you must pay off that debt instead of regular support.
