Why Do I Need to Pay Child Support if We Have Equal Custody?

 Posted on October 14, 2026 in Child Support

Child support in Illinois is meant to give children the financial support they would have had if their parents had remained together. Because of this, it is based on both parents’ incomes, not just on how much time each parent spends with the child. If one parent earns more than the other, that parent may still owe a monthly payment in 2026, even with equally split parenting time.

A Kane County, IL child support lawyer can clarify how your child support obligation is set.

How Does Illinois Calculate Child Support When Parents Have Equal Parenting Time?

Illinois uses what’s called an income shares model to determine support. The court adds both parents’ monthly net incomes together. It then finds a basic support amount on a state chart based on that combined income and the number of children. Each parent is responsible for a portion of this amount that matches their share of the combined income.

Equal parenting time affects how this calculation is made. Under 750 ILCS 5/505, parents are considered to have "shared physical care" when each one has the child for 146 or more overnights a year. In this case, the basic support amount is multiplied by 1.5. Each parent’s share of this larger amount is then multiplied by the percentage of time the child spends with the other parent. The two amounts are then compared, and the parent with the larger calculated obligation pays the difference. With equal parenting time, this is usually the parent who earns more.

Why Would I Owe Support if My Ex and I Each Have Equal Custody in Illinois?

When parents have equal parenting time and earn similar incomes, there may be little or no monthly child support. Many situations involve one parent who earns more than the other, sometimes by a significant amount. In these cases, it would be unfair for the lower-earning parent to provide for the child half the time on a smaller income. A child will also ideally have a similar standard of living in both homes.

Can Other Costs Be Split Between Parents Besides Child Support in Illinois?

Illinois courts may also divide other child-related costs between parents, usually in proportion to their incomes. These can include:

• Health insurance premiums for the child
• Medical, dental, and vision costs insurance doesn’t cover
• Child care costs so a parent can work or go to school
• School fees and extracurricular activities

Depending on how these are divided, you could owe little or no monthly support but still pay a share of these costs. You could also receive support and still owe part of them.

Can a Judge Change Child Support From What the Illinois Guidelines Say?

A judge can order a different amount if applying the guidelines would be unfair or inappropriate. They will look at things like the child’s needs, each parent’s finances, and the child’s health and schooling.

Parents can also agree to their own support terms with the approval of a judge. This ensures the agreement leaves a child with enough financial support.

Is Illinois Changing How Shared Parenting Time Affects Support?

A recent amendment to 750 ILCS 5/505 changes the shared care rule starting January 1, 2027. The threshold for shared physical care will drop from 146 overnights to 110. The law also allows courts to count certain daytime parenting hours instead of overnight stays. For parents with 110 to 145 overnights, the new formula includes adjustments based on how many nights they have the child.

If you already have a true 50/50 schedule, this change probably won’t affect you much. It may matter more if you have the child for about a third of the year. In that case, it may be worth asking an attorney whether a modification to your support order makes sense once the new rule takes effect. However, the law itself is not enough to change an existing order. Under 750 ILCS 5/510, applying the new formula to an older order requires a substantial change in circumstances.

Call a Batavia, IL Child Support Lawyer Today

If you’re not sure whether your child support order is fair, ask an attorney to review it. A review can also help you anticipate the upcoming changes to shared parenting time support calculations.

Our Kane County, IL family law attorney began his career as a prosecutor with the Kane County State’s Attorney’s Office. Attorney Van Larson was later appointed by the Judiciary as one of the county’s first Special Conflict Defenders. We can help you have confidence in your support orders or ask for modifications if needed.

Call the Law Office of Van A. Larson, P.C. at 630-879-9090 to schedule a free consultation.