Illinois is changing how child support is calculated for parents who share physical care of their children.

Beginning January 1, 2027, a new law will change the way Illinois courts calculate child support when parents have significant parenting time with their children. One of the most important changes is the reduction of the shared physical care threshold from 146 overnights per year to 110 overnights or qualifying overnight equivalents.

For parents who have parenting schedules that fall between 110 and 145 overnights, this change could affect how child support is calculated.

The new law is designed to address situations in which a parent has substantial parenting time but does not reach the previous 146-overnight threshold.

What Is Changing in Illinois Child Support in 2027?

Under the new law, which takes effect January 1, 2027, Illinois will recognize shared physical care when each parent exercises at least 110 overnights per year with the child.

The law also allows certain periods of significant parenting time that do not involve an overnight stay to potentially count as overnight equivalents.

This means that the number of nights a child spends at each parent's home will not necessarily be the only factor considered when determining whether the shared-care child support calculation applies.

The change is particularly important for parents whose parenting schedules provide substantial daytime care but previously fell short of the 146-overnight threshold.

What Is the Current 146-Overnight Rule?

Under the current Illinois child support framework, the shared-care calculation generally applies when each parent has at least 146 overnights with the child during the year.

This has sometimes created a significant difference between parenting schedules that are very close to one another.

For example, a parent with 145 overnights could be treated differently from a parent with 146 overnights under the existing framework.

The 2027 changes are intended to provide additional calculations for parents with substantial parenting time who fall below 146 overnights.

What Will Happen at 110 Overnights?

Beginning in 2027, 110 overnights will become an important threshold.

If both parents have at least 110 overnights, the court can use the shared physical care child support calculation.

The new law also creates a specific adjustment system for parents who have between 110 and 145 overnights.

The adjustment decreases as the number of overnights increases:

• 110–114 overnights: 10% adjustment
• 115–119 overnights: 9%
• 120–124 overnights: 8%
• 125–129 overnights: 7%
• 130–134 overnights: 6%
• 135–139 overnights: 4%
• 140–145 overnights: 2%

These adjustments are applied within the shared-care child support calculation and do not simply mean that child support will automatically decrease by the listed percentage.

What Are “Overnight Equivalents”?

One of the most significant changes is the introduction of overnight equivalents.

Under the new law, certain significant parenting periods that occur during separate days may be considered when determining shared physical care, even when the child does not stay overnight.

For example, a parent may have substantial periods of direct physical care during the day but return the child to the other parent's home at night.

Under the new framework, qualifying parenting time may potentially be converted into overnight equivalents for purposes of the child support calculation.

This could be particularly relevant for parents whose schedules involve extensive weekday parenting time, after-school care, or other substantial periods of direct care that do not result in overnight stays.

How Will Shared-Care Child Support Be Calculated?

The new law continues to use a shared-care formula rather than simply dividing child support equally between the parents.

When parents have shared physical care, the basic child support obligation is multiplied by 1.5 to determine the combined shared-care obligation.

The court then considers each parent's percentage share of the combined adjusted net income and the percentage of time the child spends with the other parent.

The resulting obligations are then offset against each other, with the parent who owes the larger amount generally paying the difference.

For parents with fewer than 146 overnights or overnight equivalents, the applicable adjustment is also considered.

This means that income and parenting time can both play an important role in determining the final child support amount.

Will Parents With 110 to 145 Overnights Automatically Pay Less Child Support?

Not necessarily.

The 2027 law does not mean that every parent who has between 110 and 145 overnights will automatically receive a lower child support obligation.

The calculation depends on several factors, including:

• Each parent's adjusted net income.
• The percentage of parenting time.
• The number of overnights or qualifying overnight equivalents.
• The applicable shared-care adjustment.
• The number of children.
• Other factors included in the child support calculation.
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The law also provides that the adjusted shared-care obligation cannot exceed the amount that would have been ordered under the basic child support guidelines.

Because of these factors, two parents with similar parenting schedules could still have different child support obligations.

Does This Change Parenting Time or Custody?

The child support changes do not automatically give either parent additional parenting time.

Child support and parenting time are related in the calculation of support, but they are separate legal issues.

Illinois courts determine parenting time based on the child's best interests and other factors established by Illinois law.

A parent should not assume that reaching 110 overnights automatically creates a right to an equal parenting schedule or changes an existing parenting order.

Instead, the parenting schedule and child support calculation should be evaluated separately.

What If Your Parenting Schedule Is Close to 110 Overnights?

If your current parenting schedule is close to the new threshold, it may be important to review the actual number of overnights and the amount of parenting time you exercise throughout the year.

A difference of several overnights could affect which calculation applies.

Parents should also keep accurate records of their parenting schedules, particularly when the actual schedule differs from what is written in an existing parenting order.

If significant daytime parenting time may qualify as overnight equivalents under the new law, those periods may also need to be evaluated.

Can an Existing Child Support Order Change in 2027?

The new law does not mean that every existing child support order will automatically change on January 1, 2027.

A parent seeking to change an existing child support order generally needs to follow the applicable modification process.

Depending on the circumstances, a change in parenting time, income, or other substantial circumstances may be relevant to a request for modification.

Parents should not stop or change court-ordered child support payments on their own simply because the law has changed.

Until a child support order is modified through the appropriate process, the existing order generally remains in effect.

Why Should Parents Review Their Parenting Schedule Before 2027?

Parents with shared or nearly shared parenting schedules may want to understand how the new rules could apply before the changes take effect.

A review may be particularly important if:

• Each parent has between 110 and 145 overnights.
• One parent has substantial daytime parenting time without overnight stays.
• The actual parenting schedule differs from the court-ordered schedule.
• Either parent's income has changed significantly.
• A parent is considering requesting a modification of child support.
• The parents are negotiating a new parenting plan or child support arrangement.

Understanding the new calculation can help parents make more informed decisions when negotiating parenting and support issues.

What Evidence Can Help Establish Parenting Time?

Accurate records can be important when child support depends on the amount of parenting time each parent exercises.

Depending on the circumstances, useful documentation may include:

• Parenting time calendars.
• Court-approved parenting plans.
• School or daycare records.
• Transportation records.
• Written communications between parents.
• Records showing exchanges and pickups.
• Documentation of significant daytime parenting periods.

Parents should keep records that accurately reflect the parenting schedule rather than attempting to create a schedule solely to change a child support calculation.

How Can a Family Law Attorney Help?

Illinois' 2027 child support changes may create new considerations for parents with shared parenting schedules.

An attorney can review the existing parenting order, evaluate the number of overnights and potential overnight equivalents, review the parents' financial information, and explain how the new rules may affect a particular situation.

Because child support calculations are highly dependent on the facts of each family, there is no single amount that applies to every shared-parenting arrangement.

Need Help Understanding Illinois’ 2027 Child Support Changes?

If you share parenting time with your child's other parent, the changes taking effect in 2027 may affect how child support is calculated in your case.

Weiss Ortiz Attorneys & Mediators can help parents understand their rights and legal options regarding child support, parenting time, and other Illinois family law matters.

Serving Cook County, Illinois, including Chicago, La Grange Park, Oak Brook, and Deerfield.

☎️ 773-498-4498
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Disclaimer: This article is provided for informational purposes only and does not constitute legal advice. Every family law case is different. The information in this article does not create an attorney-client relationship. Parents should consult with a qualified Illinois family law attorney about their specific circumstances.