Illinois’s new child support provisions will go into effect on January 1, 2027. This is a major revision to the Illinois Marriage and Dissolution of Marriage Act (IMDMA). This new law makes significant changes to parenting time, including allowing new methods for calculating parenting time, providing adjustments for low-income families, and requiring the annual exchange of written income documentation between the parties. The calculation changes have been released in Family Law Software. Professionals now have the option to use the new Illinois child support guidelines.
This article will outline the latest calculation updates in Illinois.
Shared Parenting Time and the Adjusted “Child Support Cliff”
Under section 505(a)(3.8) of the IMDMA, one of the most significant changes is the new law’s treatment of the “child support cliff” created by the existing 146-overnight threshold for shared physical care. Under the current law, a relatively small increase in parenting time can result in a significant reduction in child support. This situation generates custody disputes, as parents fight to get (or prevent) 146 overnights, as shared parenting time approaches 40% more disputes. This phenomenon has become commonly known to practitioners as the “child support cliff.”
The new law attempts to eliminate the cliff. Effective January 1, 2027, the threshold for applying the shared physical care formula will decrease from 146 to 110 overnights per year, or 110 “overnight equivalents.” The new law also introduces a graduated adjustment for parenting schedules between 110 and 145 overnights, effectively smoothing out the “cliff”. The drafters hope that this will reduce custody disputes.
The new law retains the existing shared care child support obligation calculations, including the 1.5 multiplier now trigged by 110 overnights or overnight equivalents. First, the combined basic child support obligation is multiplied by 1.5 to determine the shared-care support obligation. Each parent’s share of that obligation is then determined based on the parent’s percentage of the parties’ combined adjusted net income. Each parent’s resulting obligation is further adjusted based on the percentage of time the child spends with the other parent. The parents’ respective shared-care obligations are then offset, with the parent having the greater obligation generally paying the difference.
When a parent has shared physical care for fewer than 146 overnights or overnight equivalents per year, the shared care child support obligation for that parent will be increased by the percentage in the Adjustment Table, below:
| Overnights | Percentage |
| 110-114 | 10% |
| 115-119 | 9% |
| 120-124 | 8% |
| 125-129 | 7% |
| 130-134 | 6% |
| 135-139 | 4% |
| 140-145 | 2% |
Lower overnights result in a larger increase since the lower the minority time parent’s overnights, the more time the child is spending with the majority-time parent and the more costs the majority-time parent is incurring. The shared care child support obligation after the adjustment may not be greater than the amount that would have been ordered under the basic support guidelines.
Overnight Equivalents
The new law introduces “overnight equivalents,” allowing significant parenting time to count toward the shared care threshold, either as a deviation from guidelines or by agreement of the parties. Under Section 505(a)(3.8), shared physical care may apply when a parent has 110 or more overnights per year, or 110 or more overnight equivalents. An overnight equivalent may be used when a parent has significant periods of parenting time during which the child is in that parent’s physical care but does not stay overnight.
The purpose of the provision is to recognize the financial impact of substantial parenting time that may not be captured by simply counting the nights a child sleeps in each parent’s home.
The statute does not prescribe a specific formula for calculating overnight equivalents, leaving room for the court or parties to develop a reasonable methodology. Possible approaches include:
- Time-based conversion: Convert qualifying hours or days of direct parenting time into overnight equivalents. For example, treating 24 hours of qualifying care as one equivalent overnight.
- Percentage-of-time approach: Rather than converting non-overnight parenting time into nights, calculate the parent’s qualifying parenting time as a percentage of the year and use that percentage in the support calculation.
- Substantial-care approach: Give credit for recurring periods of substantial direct care based on the parent’s actual responsibilities for the child, rather than simply counting hours.
Whatever method is used, the calculation should clearly identify the qualifying parenting time and specify the methodology that the basis for the overnight equivalents, or resulting percentage of parenting time, is clear.
Whether this flexibility opens up new custody battles, or computation battles, remains to be seen.
Updated Minimum Child Support Obligations
One of the major changes affects low-income families by updating the minimum child support obligation. Under prior guidelines, there was a rebuttable presumption that a parent earning 75% or less of the federal poverty level would be ordered to pay a minimum of $40 per month per child, up to a maximum of $120 per month.
Beginning January 1, 2027, that income threshold increases from 75% to 100% of the Federal Poverty Guidelines. The amount of the presumptive minimum child support obligation itself does not change. In practical terms, more low-income parents will qualify for the minimum support obligation.
In 2026, the federal poverty level for a single individual in Illinois is $15,960 per year. So, payers with incomes below that will have the minimum order apply.
Incarceration for More Than 180 Days
When a parent will be incarcerated for more than 180 consecutive days, the new law begins with the assumption that the parent cannot pay child support. Under the amended statute, such an obligor is presumed unable to pay any amount of child support. “Incarceration” encompasses full-time confinement in a municipal, county, state, or federal facility, as well as home detention. It excludes parents on parole, work release, or any other detention alternative program that allows the parent to be employed or otherwise earn money.
If the presumption is not rebutted under defined timelines, the support obligation is set to $0. Upon release, support is reinstated by operation of law. The new provisions do not preclude the parties or the Illinois Department of Healthcare and Family Services from seeking an alternative modification based on the obligor’s actual ability to pay, or on any other basis permitted by law.
Moving Forward
The updated calculations are now available in Family Law Software for family law practitioners to prepare for the new changes. When users log into the Cloud software, users can set the start year to 2027 to see the changes. In 2027, the new guidelines will be the default.
The start year also determines which year’s basic obligation and gross-to-net tables to use. We generally receive each year’s updated tables in March of each year and update the tables in the program at that time. If you’re using the program before we release the 2027 tables, a 2027 start year will apply the new guideline and the 2026 basic obligation and gross-to-net tables.
Helpful Resources:
FLS FAQ: How do I see the Illinois 2027 guideline results?: https://www.familylawsoftware.com/ufaq/how-do-i-see-the-illinois-2027-guideline-results/
Illinois Section 5. The Illinois Marriage and Dissolution of Marriage Act (Notated): https://www.ilga.gov/Legislation/BillStatus/FullText?GAID=18&DocNum=3524&DocTypeID=SB&LegId=166555&SessionID=114