Child Support Calculations, Modifications and Appeals in DuPage County

When parents split up, one of the major issues they need to work out is child support – who is going to pay it and how much will be paid.

It makes things easier if you and the other parent can agree on what to do about child support, but if you can’t, chances are you will end up in court to have a judge decide. Even if you do agree, a judge will review your agreement to make sure it provides for at least the minimum amount according to Illinois guidelines calculations. And if your financial circumstances change, you may have to turn to the courts once again for a modification of your support agreement or to appeal a decision you feel is unfair.

The compassionate and experienced Illinois family-law attorneys at Wolfe & Stec understand the stresses of divorce and recognize the concerns parents have for the well-being of their children.  If you have any issues with child support calculations, modification, or appeal, we offer a free initial consultation to examine your individual situation and help devise solutions that are best for you and your family.

Calculating Support

In Illinois, there are specific guidelines that judges follow to set the amounts of child support. After certain deductions, the amount is calculated by percentage of the non-custodial parent’s net after-tax income, and this increases according to the number of children, as follows:

  • 20% for one child
  • 28% for two children
  • 32% for three children
  • 40% for four children
  • 45% for five children
  • 50% for six or more children

However, this formula will be changing on July 1, 2017, due to Public Act 99-764 that amends the Illinois Marriage and Dissolution of Marriage Act (IMDMA). Instead of relying on the net income of the non-custodial parent, the new law will have an income-share system.  The change will hold both parents accountable for child support based on how much they financially contributed to the combined household income while married.

Factors in the Income-Share Support Calculation

Although the law is not yet in effect, there is already a model for calculating child support that includes the following factors:

  1. Basic Child Support Obligation – The combined value of child support owed by both parents together. This is then divided proportionally between the parents, based on their individual contribution to a combined household net income.
  2. Additional Expenses – Other costs, such as child care and medical costs which are added on top of the basic child support obligation.
  3. Parenting Time – The amount of time the child spends with each parent. This determines which parent receives child support. Parents who share time may have some variations.

Shared Parenting

In Illinois, “shared parenting” occurs when each parent spends at least 146 (or 40% of) overnights with their child each year. In shared parenting situations, neither parent is considered custodial, so there is a different formula to determine the support obligations.

The General Child Support Formula is as follows:

Total Child Support Obligation equals:

(Basic child support obligation) multiplied by (Percent contributed to combined net income) plus (Additional expenses ordered by court) multiplied by (Percent contributed to combined net income).

The basic child support obligation derived from this schedule is then multiplied by 1.5 and becomes the amount parents must share. This amount is prorated based on each parent’s percentage of contribution to the combined net income.

Each parent’s child support obligation is then multiplied with the other parent’s percentage of parenting time to obtain an obligation amount for each parent. The parent who owes the greater amount of child support pays that difference to the parent who owes the lesser amount of child support.


The new law does not automatically change the terms of a child support agreement or order. However, changes in circumstances that occur from a new law can make a case for “modifying” or changing an existing child support order.

Illinois law allows either parent to ask for a modification review of an order for support every three years, or when there is a substantial change in circumstances, including an increase or decrease in income of 20%, or changes in expenses, geographical location, or health insurance rates. For the modification review, parents must fill out a Certification of Income and Expenses form (HFS 2782) to verify ability to pay, financial balances, employment status and other information.

In Illinois, parents’ obligation to support a child ends when the child turns 18, or lasts until 19 or graduation if the child is still attending high school full-time or if a child is disabled and not capable of self-support. Judges may also order parents to help with the expenses of a child over 19 who is attending college.

Getting a child support modification requires going to court.  Parents can agree to modify child support and request that the court approve their proposed change.  If the change does not satisfy Illinois law, the agreement must be adjusted.

If parents can’t agree on a modification, a judge will have to determine whether child support should be modified. The parent requesting the change will need to file legal paperwork asking a court to change child support and giving the reasons why.


If you requested a modification that was not granted or you disagree with the judge’s decision, you have the right to:

  1. Ask the court to reconsider its decision by filing a Motion for Reconsideration. You must state why you think that the court was wrong when it made the ruling.
  2. Appeal the decision to a higher court and ask it to examine the original court’s decision. Usually, you must file your appeal within 30 days from the date of the judge’s decision.

Contact Us for Help and a Free Consultation

Child support laws, modifications, and appeals can be complicated, and you will have to deal with the results for years. If you have questions about calculating child support or modifying or appealing existing support orders, you should contact an attorney to be sure your rights are protected. The skilled Illinois family-law attorneys at Wolfe & Stec, Ltd. know the laws, the courts and the system and can guide you through the process.  We represent and advise clients in all types of child custody matters and have a long history of success.

Don’t delay. For a free initial consultation with an experienced and compassionate DuPage County custody lawyer, contact us online or call 630-305-0222 for a free initial consultation.

Attorney Natalie Stec

Natalie M. Stec, born and raised in Illinois, and earned her Bachelor of Science from the University of Illinois at Urbana-Champaign. Her practice has been concentrated in significant pre and post decree marital and family law cases; including custody, visitation, support, and paternity matters. She has important criminal defense experience in both misdemeanor and felony cases. She is a very dedicated and passionate litigator. [ Attorney Bio ]

Woodridge Illinois Law Firm

3321 Hobson Road, Suite B
Woodridge, IL 60517
Phone: 630-305-0222

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