Effective January 1, 2027, Illinois will implement new child support thresholds that reduce the number of overnights required for support calculations. This update aims to create a fairer, more realistic system by recognizing that parenting responsibilities extend beyond where a child sleeps.
Before reviewing the changes, it is helpful to understand how the current income shares model is applied for comparison:
Illinois currently utilizes the Income Shares Model to determine child support obligations. This approach ensures children receive the same level of financial support they would have if their parents remained in a single household. Under this model, support is calculated based on the combined income of both parents, rather than a fixed percentage of only one parent’s earnings.
A Step-by-Step Guide to the Income Shares Model
- Step 1: The Court calculates each parent’s monthly net income by totaling all income sources—including wages, salaries, bonuses, commissions, and self-employment earnings—and subtracting taxes, Social Security, Medicare, and other mandatory deductions.
- Step 2: Combine both parents’ net incomes and locate the resulting figure on the Illinois Department of Healthcare and Family Services (HFS) Schedule of Basic Child Support Obligations. Based on the number of children, this identifies the estimated amount parents at that combined income level typically spend on their children.
- Step 3: Each parent is assigned a percentage share of the combined net income. In a standard (non-shared) arrangement, the parent with less parenting time pays their proportional share of the basic obligation to the other parent. If parents share physical custody, a specialized calculation applies (see below).
Child Support Calculation Example: Non-Shared Physical Custody Arrangements
Parent A earns a monthly net income of $6,000 and Parent B earns a monthly net income of $4,000, resulting in a total combined monthly net income of $10,000.
Consult the HFS Schedule of Basic Child Support Obligations. For example, a combined income of $10,000 results in a basic child support obligation of $1,800 for one child.
Parent A contributes 60% of the total income, resulting in a support obligation of $1,080 (60% of the $1,800 total). Parent B contributes 40%, amounting to $720.
When Parent B has primary physical custody, Parent A pays approximately $1,080 per month, which represents their income-based percentage of the basic guideline amount.
Shared Parenting Formula
Under current law, shared physical care is established when each parent has the child for at least 146 overnights per year—approximately 40% of the year. Once this threshold is met:
- The basic child support obligation is adjusted by a factor of 1.5 to reflect the increased costs associated with maintaining two separate households.
- Each parent’s portion of the total shared care obligation is determined by their proportional share of the combined net income.
- Each parent’s respective share is multiplied by the percentage of time the child spends in the other parent’s care.
- The two resulting amounts are offset, and the parent with the higher obligation pays the difference.
Example of Calculating Support When Parents Share Physical Custody
Effective through December 31, 2026, if each parent exercises 146 or more overnights annually (representing approximately 40% of the parenting time):
Divide the total amount based on income percentages: Parent A’s 60% share is $1,620, and Parent B’s 40% share is $1,080.
Calculations are adjusted to reflect the actual time each parent spends with the children. When parenting time is shared equally, the obligations offset one another: the higher-earning parent pays the difference—approximately $540 per month. Even with an equal split of time, the higher earner typically maintains a support obligation.
If a parent is allocated 140 or fewer overnights, the standard (non-shared) calculation formula applies, resulting in a higher payment obligation.
Effective January 1, 2027, the shared care formula will be updated to lower the physical care threshold from 146 overnights to 110 overnights or their equivalent (significant daytime care provided without an overnight stay). While the 1.5 multiplier and offset remain unchanged, this revision ensures a more equitable child support calculation that better reflects the specific care arrangements of each family.
Effective January 1, 2027, new Illinois shared-care rules—defined by 110 or more overnights and specific formula adjustments—will change how child support is calculated for qualifying cases. These rules do not automatically update existing orders; therefore, a formal legal modification is required to adjust current child support obligations.
To qualify for the new lower threshold (110 overnights or significant daytime equivalents) and the shared care formula, a parent must file a petition to modify child support with the court.
Modifying a child support order requires a substantial change in circumstances. Under the new law, a recalculation may be warranted if parenting time meets the 110-overnight threshold (or its equivalent), resulting in a significant change to the support obligation. A recalculation may also be pursued in conjunction with other material changes in circumstances.
Consult with an Experienced Illinois Child Support Attorney for Expert Legal Guidance.
With the new year approaching, now is an excellent time to consult an experienced family law attorney to determine if a child support modification is warranted. By reviewing current income figures and overnight care schedules, you can ensure your order accurately reflects your current situation. Contact Ronald L. Bell & Associates today for more information at 847-495-6000.
