Joint Custody Illinois: What It Actually Means Under Current Law

Illinois Doesn't Use the Term "Joint Custody" Anymore

If you're searching for information on joint custody in Illinois, the first thing to know is that Illinois law retired that terminology in 2016. The Illinois Marriage and Dissolution of Marriage Act (IMDMA) replaced "legal custody," "physical custody," and "visitation" with two separate concepts:

• Allocation of significant decision-making responsibilities — who makes major decisions about education, health, religion, and extracurricular activities
• Parenting time — the physical schedule of when the child is with each parent

This matters because the old term "joint custody" blurred two very different things together. Under current Illinois law, you can have joint decision-making authority while one parent has 70% of the parenting time. Or you can have a true 50/50 time split with one parent holding sole decision-making power over health choices.

The two are evaluated independently by the court.

What "Joint Decision-Making" Looks Like

Joint allocation of significant decision-making means both parents share authority over major life decisions in one or more of the four statutory categories: education, health, religion, and extracurricular activities.

Courts can also split these categories. One parent might have sole decision-making for education (choosing the school) while both share authority over healthcare decisions. This category-by-category approach often works better than an all-or-nothing arrangement, particularly when parents disagree on specific topics but cooperate well on others.

The court evaluates several factors when deciding whether joint decision-making is appropriate, including each parent's participation in past decision-making, the parents' ability to cooperate, and the level of conflict between them. If the parents cannot cooperate in a way consistent with the child's best interests, the court may allocate a category to one parent.

Does 50/50 Parenting Time Happen in Illinois?

Yes, and it's increasingly common. Illinois courts don't have a statutory presumption favoring either parent or any particular split. The court applies the best-interests factors under 750 ILCS 5/602.7, which include the child's wishes, each parent's caretaking history over the preceding 24 months (or since birth if the child is under 2), the distance between homes, and each parent's willingness to foster a relationship with the other parent.

Parents who want a 50/50 schedule need to demonstrate that it's workable — meaning the homes are close enough for school transitions, both parents can manage school-day mornings and evenings, and the child has shown they can handle frequent transitions.

Common 50/50 schedules in Illinois include alternating weeks, 2-2-5-5, and 2-2-3 rotations. Each has different transition frequencies that suit different ages. A 2-2-3 schedule works well for younger children who need shorter stretches away from each parent, while alternating weeks reduce transitions for school-age kids.

The Financial Connection You Can't Ignore

Your parenting-time split directly affects child support. Under Illinois's Income Shares Model, the standard calculation assumes one parent has the majority of overnights. But if the non-majority parent has 146 or more overnights per year — which any true 50/50 schedule exceeds — the shared-care formula kicks in. That formula multiplies the basic support obligation by 1.5 and offsets the two parents' shares against each other.

Starting January 2027, SB3524 lowers the shared-care threshold to at least 110 overnights for each parent. Under either rule, the exact overnight count has real financial stakes. Equal parenting time doesn't automatically eliminate child support — if there's an income gap between parents, the higher earner still pays.

Sole Allocation: When One Parent Gets Everything

Under 750 ILCS 5/602.5, the court can allocate all significant decision-making responsibilities to one parent when that allocation serves the child's best interests; the statute does not require each parent to receive decision-making responsibilities. This is the equivalent of what used to be called "sole custody."

Evidence of domestic violence, severe substance abuse, parental alienation, or an inability to communicate about basic decisions may support sole allocation or restrictions, depending on the facts.

A parent seeking sole allocation should present evidence explaining why joint decision-making would not serve the child's best interests, such as documentation of conflict, police reports, or testimony from therapists and school personnel.

Moving Forward with Your Arrangement

Whether you're aiming for joint decision-making, a 50/50 schedule, or some other arrangement, the process starts with drafting a parenting plan under 750 ILCS 5/602.10 — the proposed plan is generally due within 120 days after service or filing of an appearance, as applicable.

The Illinois Child Custody & Parenting Plan Guide includes a decision-making matrix that walks you through each of the four categories, plus overnight-tracking worksheets that show exactly how your proposed schedule maps to the child support thresholds.

See more Illinois guides →