Child support calculations in Illinois were updated in 2026, but that does not mean the state adopted an entirely new child support system. Illinois continues to use the Income Shares model, which considers both parents’ incomes and estimates the amount that would have been spent supporting the children if the parents lived together.
What changed are the financial tables used when applying that model. The Illinois Department of Healthcare and Family Services revised the Schedule of Basic Child Support Obligations and the Gross-to-Net Income Conversion Table effective March 20, 2026.
For parents who are divorcing, separating or reviewing an existing agreement, the updated figures provide a reason to make sure they are using current information. They also offer an opportunity to look beyond the basic calculation and discuss the full range of expenses involved in raising their children.
What Changed in the Illinois Child Support Guidelines?
Illinois has updated its child support tables annually since 2024 to reflect current economic conditions. According to the Illinois Department of Healthcare and Family Services, both the Schedule of Basic Child Support Obligations and the Gross-to-Net Income Conversion Table were most recently revised effective March 20, 2026.
The Schedule of Basic Child Support Obligations estimates the amount parents at different combined income levels would ordinarily spend supporting their children. The gross-to-net table provides standardized tax amounts that may be used when converting gross income into net income for the calculation.
Using an outdated table could produce a different estimate than one based on the current figures. Parents, mediators and attorneys should therefore confirm that any child support estimate prepared in 2026 uses the updated information.
The state also provides an online Illinois Child Support Estimator. The estimator can provide a useful starting point, but it does not determine what a court will order or address every expense a family may need to discuss.
How Is Child Support Calculated in Illinois?
Illinois generally begins by determining each parent’s net income. The parents’ net incomes are then combined and compared with the state’s Schedule of Basic Child Support Obligations. Each parent is allocated a proportional share of the resulting basic support obligation.
The calculation may involve:
- Each parent’s income from employment and other applicable sources
- Allowable adjustments or deductions
- The number of children covered by the calculation
- The number of nights the children spend with each parent
- Whether the parenting arrangement qualifies for the shared physical care calculation
Parenting time can affect the calculation, but equal or nearly equal parenting time does not automatically eliminate child support. Differences in the parents’ incomes and the details of the parenting schedule may still result in one parent having a support obligation.
The guideline calculation is only one part of the family’s financial discussion. Parents may also need to consider health insurance, uncovered medical and dental costs, childcare, school expenses, extracurricular activities and other costs that are not fully addressed by the basic support figure.
The Guideline Amount Does Not Answer Every Financial Question
A child support calculation produces a number, but families generally need a more complete plan.
For example, parents may need to decide how they will handle:
- Health, dental and vision insurance
- Medical, dental, therapy and prescription costs not covered by insurance
- Daycare, before-school and after-school care
- School registration, supplies, technology and activity fees
- Sports, lessons, camps and extracurricular activities
- Transportation and vehicle-related expenses for older children
- Cellphones, clothing and personal expenses
- College savings and future educational costs
Some of these expenses may be allocated in addition to basic child support. Others may be addressed through an agreement that explains what must be approved in advance, how costs will be divided and when reimbursement is expected.
Clear terms can be especially helpful for expenses that change from year to year. A parenting agreement that simply says the parents will divide “agreed expenses” may create future conflict if it does not explain how an expense becomes agreed upon.
How Mediation Can Help Parents Develop a Complete Plan
In child support mediation, parents can review the current guideline estimate while also discussing how their children’s actual needs will be handled.
The mediator does not represent either parent or decide what the support amount should be. Instead, the mediator helps the parents identify the necessary information, understand where they agree or disagree and consider possible approaches.
The discussion may include questions such as:
- What income information must each parent provide?
- Is either parent’s income variable, seasonal or self-employment based?
- How will bonuses, commissions or overtime be addressed?
- Which parent will provide health insurance?
- How will uncovered medical costs be divided?
- Which activities require advance approval?
- How will changing school, childcare or transportation costs be handled?
- When should the parents exchange updated financial information?
When parents reach proposed terms, the mediator can record them in a memorandum of understanding. Each parent may then have the proposed agreement reviewed by an independent attorney before it is incorporated into the documents submitted to the court.
Do the 2026 Tables Automatically Change an Existing Child Support Order?
The updated tables do not automatically recalculate or change an existing child support order. The amount in the current order generally remains in effect unless the parents obtain an approved modification.
A modification may become relevant when there has been a substantial change in circumstances. Depending on the situation, that could involve a lasting increase or decrease in income, a job loss, a change in the parenting schedule, different childcare needs or a change in health insurance costs.
Parents should not informally stop, reduce or change court-ordered payments on their own. Even when both parents believe a different amount is appropriate, the existing order should be addressed through the proper legal process.
Mediation may help parents discuss a proposed modification before presenting an agreement to the court. Independent legal advice remains important because the mediator is neutral and does not act as either parent’s attorney.
Preparing for a Child Support Discussion
Parents can make mediation more efficient by gathering current and complete information before discussing support.
Helpful records may include:
- Recent pay stubs
- Federal and state income tax returns
- W-2s, 1099s and documentation of other income
- Information about bonuses, commissions or overtime
- Health insurance premiums and coverage details
- Childcare invoices
- Records of recurring medical or therapy expenses
- School and extracurricular costs
- The current parenting schedule
Parents should also identify expenses that are likely to change. A child entering daycare, beginning school, joining a competitive activity, starting to drive or preparing for college may significantly alter the family’s financial needs.
The objective is not merely to complete a formula. It is to develop terms that are understandable, workable and detailed enough to reduce future uncertainty.
