Illinois child support law is changing. Senate Bill 3524 amends Sections 505 and 510 of the Illinois Marriage and Dissolution of Marriage Act, which are the provisions that govern child support calculations and child support modifications. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026); 750 ILCS 5/505; 750 ILCS 5/510. The Illinois General Assembly’s bill status page identifies SB 3524 as “Child Support Changes” and states that the bill passed both houses on May 21, 2026. Bill Status of S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026).
These changes are scheduled to take effect on January 1, 2027. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026). The new law alters how Illinois courts calculate child support in shared parenting cases, expands the concept of shared physical care, creates a new adjustment table for parents with 110 to 145 overnights, changes the minimum child support rule for low-income obligors, and creates a clearer process for child support modification when a parent is incarcerated. Id.
Even before these changes, Illinois child support was based on an “Income Shares” model. The Illinois Department of Healthcare and Family Services states that Illinois replaced its former percentage-of-income model with the Income Shares Guideline Model effective July 1, 2017. Ill. Dep’t of Healthcare & Fam. Servs., Income Shares. HFS explains that Illinois child support guidelines are found in Section 505 of the Illinois Marriage and Dissolution of Marriage Act. Id.; 750 ILCS 5/505.
The Income Shares model means that child support is not based solely on the paying parent’s income. Section 505 requires the Illinois court to “determine each parent’s monthly net income,” “add the parents’ monthly net incomes together,” “select the corresponding appropriate amount from the schedule of basic child support obligations,” and “calculate each parent’s percentage share of the basic child support obligation.” 750 ILCS 5/505(a)(1.5)(A)-(D).
To be clear, SB 3524 does not replace the Income Shares model. SB 3524 changes how that model is applied in multiple situations.
Illinois Child Support And Shared Parenting Before SB 3524
One of the most significant changes concerns shared parenting.
Under the current Illinois child support framework, the shared-care calculation is tied to the number of overnights each parent exercises with the child. Before SB 3524, the shared-care benchmark was 146 overnights per year. Senator Michael Hastings’ office explained the bill lowers “the threshold for applying the shared-care formula from 146 overnights per year to 110,” which would expand eligibility to families where both parents play a significant caregiving role. Press Release, Sen. Michael E. Hastings, Hastings Backs Bill Updating Illinois Child Support Rules For Shared Parenting (Apr. 20, 2026).
Because many Illinois parents have substantial parenting time without reaching 146 overnights per year, this change is significant. A parent may have a child multiple evenings per week, handle transportation, activities, meals, or other daily care, yet still fall short of the 146-overnight threshold. SB 3524 reflects the reality that shared parenting is not always captured by merely counting where the child sleeps at night.
Shared Physical Care Will Include 110 Overnights Or Overnight Equivalents
SB 3524 creates a new definition of shared physical care.
The amended statute states:
“Shared physical care means each parent exercises 110 or more overnights per year with the child, or 110 or more overnight equivalents as determined by a court as a deviation from guidelines or upon agreement by the parties.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.8)(1)).
This is the main change in the new law. Put simply, beginning January 1, 2027, a parent can qualify for shared physical care with 110 or more overnights rather than 146. A parent can also qualify through overnight equivalents if the court determines that the parent’s non-overnight parenting time should count, or if the parents agree that the time should count. Id. The new 110-overnight threshold will be especially important in cases involving child support and 50/50 custody in Illinois, where both parenting time and income can impact the calculation.
The statute also explains what an overnight equivalent actually means:
“Overnight equivalents are calculated by using a method other than overnights if the parent has significant parenting time periods on separate days in which the child is in the parent’s physical care and under the direct care of that parent but does not stay overnight.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.8)(1)).
This language shifts the analysis beyond a rigid sleep-counting approach. The question becomes not simply, “How many nights did the child sleep at each parent’s home?” It may now also be, “Did the parent provide significant direct care on separate days, even though the child did not stay overnight?” Senator Hastings’ office explained that the bill accounts for “substantial daytime care” when the child is in the parent’s physical care and under the parent’s direct supervision. Press Release, Sen. Michael E. Hastings, Hastings Backs Bill Updating Illinois Child Support Rules for Shared Parenting (Apr. 20, 2026).
I believe that this is significant for parenting schedules built around work hours, school schedules, activities, transportation, or other daytime caregiving responsibilities.
How The New Illinois Shared Care Child Support Calculation Works
SB 3524 does not just lower the shared-care threshold. The bill also lays out how courts are supposed to calculate child support when parents have shared physical care.
The amended statute explains:
“If parents have shared physical care of a child, the basic child support obligation shall be multiplied by 1.5 to calculate the combined shared care child support obligation.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.8)(2)).
Illinois’ shared-care child support framework already has this 1.5 multiplier. Currently, HFS provides a Shared Physical Care Support Obligation Worksheet as part of its Income Shares materials, along with the basic support worksheet and child support estimator. Ill. Dep’t of Healthcare & Fam. Servs., Income Shares. The HFS shared-care worksheet likewise uses the 1.5 multiplier to calculate the shared physical care support obligation. The amended law keeps the shared-care structure but applies that structure to a broader range of parenting-time arrangements.
The amended statute separately addresses situations in which each parent exercises 146 or more overnights per year; however, SB 3524 expands the shared-care framework because it adds a calculation for parents with 110 or more overnights or overnight equivalents and an adjustment table for cases below 146. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.8)(1), (3.8)(3), (3.8)(4)).
Once the basic child support obligation is multiplied by 1.5, the Illinois court determines each parent’s portion of the shared-care obligation; this is based on that parent’s percentage share of the parents’ combined adjusted net income. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.8)(2)). Next, the statute states that each parent’s shared-care obligation is calculated by multiplying that parent’s portion of the shared-care support obligation by the percentage of time the child spends with the other parent. Id.
Lastly, the parents’ respective obligations are offset. The statute states, “[t]he respective shared care child support obligations are then offset, with the parent owing more paying the difference in child support.” Id.
This essentially means that shared physical care does not automatically eliminate child support. Even when both parents exercise substantial parenting time, one parent may still owe support after the calculation is completed. The calculation considers both parents’ incomes, the basic child support obligation, the 1.5 shared-care multiplier, the child’s time with each parent, and the offset between the two calculated obligations.
The New Adjustment Table For 110 To 145 Overnights
SB 3524 provides an updated adjustment table for parents who have shared physical care but do not reach 146 overnights or overnight equivalents per year.
The amended statute states:
“When a parent has shared physical care for less than 146 overnights or overnight equivalents per year, the shared care child support obligation for that parent shall be increased by the percentage in the Adjustment Table below.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.8)(3)).
The adjustment table is as follows:
| Number of Overnights | Percentage |
| 110-114 | 10% |
| 115-119 | 9% |
| 120-124 | 8% |
| 125-129 | 7% |
| 130-134 | 6% |
| 135-139 | 4% |
| 140-145 | 2% |
S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.8)(3)).
The new law does not treat every parent with 110 or more overnights in the same manner. A parent with 112 overnights is not treated just like a parent with 144 overnights. Rather, the adjustment gradually decreases as the parent gets closer to 146 overnights.
The amended statute includes a cap: “[t]he shared care child support obligation after adjustment may not be greater than the amount that would have been ordered under the basic support guidelines in any event.” Id.
This is important, as shared-care calculation should not result in a child support obligation that is higher than the normal basic-guidelines amount. Senator Hastings’ office made this very point, stating that any resulting obligation would be capped so that it does not exceed the amount required under the basic guidelines. Press Release, Sen. Michael E. Hastings, Hastings Backs Bill Updating Illinois Child Support Rules for Shared Parenting (Apr. 20, 2026).
Overall, this updated table softens the old 146-overnight line. In my experience, parents often focus heavily on whether the parenting schedule reached 146 overnights. However, SB 3524 creates a middle category for parents with substantial parenting time who fall short of 146 overnights but still have at least 110 overnights or qualifying overnight equivalents.
Minimum Illinois Child Support For Low-Income Parents
Additionally, SB 3524 changes Illinois’s minimum child support rule for low-income obligors.
The amended statute explains:
“There is a rebuttable presumption that a minimum child support obligation of $40 per month, per child, will be entered for an obligor who has actual or imputed gross income at or less than 100% of the most recent United States Department of Health and Human Services Federal Poverty Guidelines for a family of one person, with a maximum total child support obligation for that obligor of $120 per month to be divided equally among all of the obligor’s children.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.3a)).
Before SB 3524, the minimum-support presumption applied when the obligor’s actual or imputed gross income was at or below 75% of the most recent Federal Poverty Guidelines for a family of one person. SB 3524 changes that threshold to 100%. Id. The Illinois General Assembly’s bill text plainly demonstrates the change by replacing “75%” with “100%” in Section 505(a)(3.3a).
However, the minimum child support amount does not change; the statute uses $40 per month, per child, with a maximum total child support obligation of $120 per month. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.3a)). The important alteration is the income threshold used to decide who falls within the minimum-support presumption.
More low-income obligors may now fall within the minimum-support rule. The Federal Poverty Guidelines are issued by the United States Department of Health and Human Services and are updated annually. HHS shows that the 2026 poverty guideline for a household of one in the 48 contiguous states and the District of Columbia is $15,960. Annual Update of the HHS Poverty Guidelines, 91 Fed. Reg. 5917 (Jan. 15, 2026).
The minimum-support rule stays as a rebuttable presumption. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.3a)). Put simply, the statute presumes the minimum amount applies when the obligor’s income falls within the statutory threshold; however, the presumption can be challenged in appropriate cases. This change recognizes that low-income parents can still have support obligations, while limiting those obligations for parents whose income is at or below the federal poverty guideline.
SB 3524 further leaves in place the separate zero-dollar child support order provision. Under Section 505(a)(3.3b), “[f]or parents with no gross income, who receive only means-tested assistance, or who cannot work due to a medically proven disability, incarceration, or institutionalization, there is a rebuttable presumption that the $40 per month minimum support order is inapplicable and a zero dollar order shall be entered.” 750 ILCS 5/505(a)(3.3b). Importantly, this provision is distinct from the minimum-support presumption in Section 505(a)(3.3a). Some parents can fall under the $40-per-month minimum-support rule, while other parents may qualify for a rebuttable presumption that even the $40 minimum does not apply. The zero-dollar provision is separate from the minimum-support rule and may matter when a parent is seeking zero child support in Illinois.
Illinois Child Support When A Parent Is Incarcerated
When a parent is incarcerated, SB 3524 creates a straightforward child support modification process.
Currently, Section 510 governs modification and termination of support obligations. SB 3524 adds that an order for child support can be modified “upon a showing that a parent will be incarcerated for more than 180 consecutive days or released from incarceration lasting more than 180 consecutive days.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/510(a)(3)).
The fully amended statute explains:
“A parent incarcerated for more than 180 days is presumed to be unable to pay any amount of child support, and this presumption may be rebutted by evidence establishing the ability to pay child support during incarceration.” Id.
Importantly, this does not mean each incarcerated parent automatically avoids child support. Instead, SB 3524 creates a rebuttable presumption, which is that a parent incarcerated for more than 180 days is presumed unable to pay support, but another party may present evidence showing the parent still can pay. Id. Similarly, the Illinois General Assembly’s bill status page summarizes the bill as creating a presumption that a parent incarcerated for more than 180 days is unable to pay child support, while allowing that presumption to be rebutted. Bill Status of S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026).
SB 3524 defines incarceration for purposes of this rule. The statute states:
“‘Incarceration,’ for the purposes of this Section, means confinement of a parent on a full-time basis in a place of detention, including home detention or a municipal, county, state, or federal prison, jail, or detention.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/510(a)(3)(A)).
The definition does not include “a parent on parole, work release, or any other detention alternative program that allows the parent to be employed or otherwise earn money.” Id.
Further, the updated law creates a notice procedure. In a case where a parent will be incarcerated for more than 180 consecutive days, the parent’s support obligation can be modified to $0.00 by operation of law if the Department of Healthcare and Family Services or another party files a notice of incarceration with the circuit court clerk, provides notice to all parties, and no written objection is filed within 45 days of the effective date of the notice. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/510(a)(3)(C)).
The notice of incarceration must include “the name and address of the facility where the parent is incarcerated,” “the parent’s inmate number,” and “the beginning and projected end dates of incarceration, if known, or, if unknown, the reason a date cannot be provided.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/510(a)(3)(D)). The notice also needs to state that “failure to file a written objection within 45 days” will result in the parent’s support obligation being “reduced to $0.00 as of the effective date of the notice of incarceration.” Id.
Where a party files a timely objection to the notice of incarceration, the amended statute requires the Illinois court to “set the matter for hearing as soon as practicable and send notice of the hearing date to all parties including HFS.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/510(a)(3)(G)). At the hearing, “[t]he presumption that the parent is unable to pay any amount of support may be rebutted by a preponderance of the evidence” by showing that “the parent has substantial income or assets that can be used to satisfy the child support obligation during incarceration” or that “the parent is not, or will not be, incarcerated for more than 180 consecutive days.” Id.
Finally, SB 3524 addresses what happens after a parent is released from incarceration. A parent released after more than 180 days is presumed to be able to pay the minimum child support amount after 90 days from release. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/510(a)(3)). The statute makes clear, though, that any party, including HFS, may still seek a modification based on the parent’s actual ability to pay during or after incarceration. Id.
Annual Income And Employment Reporting Requirements
SB 3524 also changes what information must be exchanged after a child support order is entered.
The amended statute provides:
“An order entered under this Section shall include a provision requiring both parents to exchange information annually, and either parent to report to the other parent and to the Clerk of Court within 10 days each time either parent obtains new employment, and each time either parent’s employment is terminated for any reason.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(h)).
This is broader than simply requiring the paying parent to report employment changes. The amended language requires both parents to exchange information annually. It also requires either parent to report new employment or termination of employment within 10 days. Id.
The statute further provides that the information exchanged or reported must be in writing and must verify the parent’s net income as defined in Section 505. Id. In the case of new employment, the report must include the name and address of the new employer. Id.
This reporting requirement matters because child support depends heavily on income. Under the Income Shares model, the court calculates support by determining each parent’s monthly net income, adding the parents’ monthly net incomes together, selecting the appropriate support amount from the schedule of basic child support obligations, and calculating each parent’s percentage share of the obligation. 750 ILCS 5/505(a)(1.5)(A)-(D). Annual income disclosure gives both parents updated information that may be relevant to whether the support amount still reflects the parents’ actual incomes.
SB 3524 also keeps consequences for failing to report employment changes. The amended statute states that failure to report new employment or termination of current employment, “if coupled with nonpayment of support for a period in excess of 60 days, is indirect criminal contempt.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(h)).
Put simply, SB 3524 does not only change how support is calculated at the beginning of a case. The law also requires continuing financial transparency after the support order is entered. That continuing disclosure requirement may make it easier for parents to identify when a support order should be reviewed, enforced, or modified.
Modifying Existing Child Support Orders Under SB 3524
SB 3524 makes many changes to Illinois child support law, but the new law does not mean every existing child support order will automatically change on January 1, 2027.
Section 510 of the Illinois Marriage and Dissolution of Marriage Act governs modification of child support orders, including modification based on a substantial change in circumstances. Under Section 510, an order for child support may be modified “upon a showing of a substantial change in circumstances.” 750 ILCS 5/510(a)(1). Section 510 also allows a child support order to be modified “without the necessity of showing a substantial change in circumstances” in certain cases. 750 ILCS 5/510(a)(2). One such case arises “upon a showing of an inconsistency of at least 20%, but no less than $10 per month, between the amount of the existing order and the amount of child support that results from application of the guidelines specified in Section 505 of this Act.” 750 ILCS 5/510(a)(2)(A).
However, that exception is limited. The statute states that subparagraph (a)(2)(A) only applies in situations where a party is receiving child support enforcement services from HFS and at least 36 months have passed since the support order was entered or last modified. 750 ILCS 5/510(a).
SB 3524 also creates a modification provision for incarceration. A child support order may be modified “upon a showing that a parent will be incarcerated for more than 180 consecutive days or released from incarceration lasting more than 180 consecutive days.” S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/510(a)(3)).
The overall takeaway is that parents with existing orders cannot assume the order changes simply because the statute changes. SB 3524 creates new rules, but a parent still needs a legal basis and a proper procedural path for changing an existing child support order.
What Illinois Parents Must Know Before 2027
SB 3524 changes several important aspects of Illinois child support law.
The biggest change is the new shared-care framework. Starting on January 1, 2027, shared physical care can apply when each parent exercises 110 or more overnights per year, or 110 or more overnight equivalents. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.8)(1)). The law also creates a new adjustment table for parents who have at least 110 overnights or overnight equivalents but fewer than 146. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.8)(3)).
The law further changes the minimum-support threshold for low-income obligors from 75% to 100% of the Federal Poverty Guidelines for a family of one person, while keeping the $40 per month per child amount and the $120 per month cap. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(a)(3.3a)).
Finally, SB 3524 creates a detailed process for child support when a parent is incarcerated for more than 180 consecutive days and requires ongoing annual income disclosure and employment reporting. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/505(h), 510(a)(3)).
The main point for Illinois parents is that child support disputes may become less focused on a single 146-overnight threshold and more centered on the actual parenting arrangement. Each parent’s income, the child’s time with each parent, and whether substantial non-overnight parenting time should count as an overnight equivalent can all become more important. If you are a parent with a current or future child support order, you should pay close attention to parenting-time schedules, income disclosures, and circumstances that can support modification under the amended statute.
Contact Russell D. Knight to discuss how Illinois child support law may apply to your parenting schedule, income, or modification request. Russell has practiced family law as a Chicago divorce lawyer since 2006 and represents parents in child support, parenting time, and other Illinois family law matters.
References used in the Illinois Child Support Changes Coming In 2027 Article
Illinois General Assembly, Bill Status of S.B. 3524, 104th General Assembly.
Illinois General Assembly, Full Text of S.B. 3524, 104th General Assembly.
Illinois General Assembly, 750 ILCS 5/505, Child Support.
Illinois General Assembly, 750 ILCS 5/510, Modification and Termination of Provisions for Maintenance, Support, Educational Expenses, and Property Disposition.
Illinois Department of Healthcare and Family Services, Income Shares.
Illinois Department of Healthcare and Family Services, Shared Physical Care Support Obligation Worksheet.
Senator Michael E. Hastings, Hastings Backs Bill Updating Illinois Child Support Rules For Shared Parenting.
U.S. Department of Health and Human Services, Office of the Assistant Secretary for Planning and Evaluation, 2026 Poverty Guidelines Computations.
Federal Register, Annual Update of the HHS Poverty Guidelines, 91 Fed. Reg. 5917 (Jan. 15, 2026).
Frequently Asked Questions About Illinois Child Support Changes In 2027
When do the Illinois child support changes take effect? SB 3524 is scheduled to take effect on January 1, 2027.
What is the biggest Illinois child support change in SB 3524? The biggest change is that shared physical care can apply when each parent has 110 or more overnights or overnight equivalents.
What are overnight equivalents in Illinois child support? Overnight equivalents are significant non-overnight parenting time frames where a child is in a parent’s physical care and under that parent’s direct care.
Does shared physical care eliminate child support in Illinois? No, shared physical care does not instantly eliminate child support because the Illinois court still applies the Income Shares calculation, the 1.5 multiplier, parenting-time percentages, and the offset.
Can child support be reduced if a parent is incarcerated? Yes, SB 3524 creates a modification process when a parent will be incarcerated for more than 180 consecutive days, along with a rebuttable presumption that the parent cannot pay support during incarceration. S.B. 3524, 104th Gen. Assemb., Reg. Sess. (Ill. 2026) (amending 750 ILCS 5/510(a)(3)).
