New Child Support Law Effective July 1, 2017

Starting July 1, 2017 Illinois will have the biggest change to the Illinois Child Support statute in decades. The net income, percentage of income model has been the law of the land, in Illinois, for over 30 years. The main criticism of the current law is that it fails to account for both parents’ income and the standard of living the child would have enjoyed had the family remained intact. Under the new law, gone is the percentage model. Illinois will be the 40th state to implement an income shares model. To calculate child support based upon the parent’s combined adjusted net income estimated to have been allocated to the child if the parents and children were living in an intact household. 750 ILCS 5/505 (a)(1)(D). Therefore underlying public policy for the new law is to account for the standard of living the child would have had, to reward parents who have physical possession of the child for half the year, and to make each parent contribute to the cost of raising the child.



Currently, Illinois follows the net income/percentage model, whereby child support is calculated based upon a percentage of the net income of the obligor. Illinois child support is 20% for one child, 28% for two, 32% for three, 40% for four, and 50% for five or more children. The real variable is what determines net income. Under the current statute, some of the things that are deducted from gross income, to arrive at net income include, but are not limited to, mandatory union dues, health insurance, life insurance, student loans, and other expenses necessary for the production of income and various business expenses.


Under the new income shares model, three main factors will be considered in determining child support: 1) Basic Child Support Obligation: A combined value of child support owed by BOTH parents, divided proportionally between the parents (based upon their relative incomes); 2)Additional Expenses: Other additional costs, which may include child care costs, extracurricular activities and outstanding medical or health insurance expenses; and 3) Parenting Time: The amount of time the child spends with each parent. Parties with either split or shared parenting time will see a variation in the calculation, and there will be a huge benefit to having shared or split parenting time, for otherwise non-residential parents. The Illinois Department of Healthcare and Family Service is preparing a conversion table, for converting gross income to net income using the Standardized Tax Amount formula. The calculation from gross income to net income lists a parent’s gross income and converts it to net income based upon the standardized tax amount formula and the number of children. And there would be a rebuttable presumption that the resulting child support amount is correct Income under the new law shall be defined in 750 ILCS 5/505 (a) (3). The income shares legislation defines net income as gross income minus either the standardized tax amount (formula) or the individualized tax amount (formula). By way of illustration, maintenance, SSDI and retirement benefits are included as income for child support purposes. Whereas public aid such as SNAP, TANF and child support for other children in the household are not income.


Current Model- Percentage of Obligor

Only considers the obligor’s income.
Takes a simple percentage of obligor’s net income.
Does not consider the cost to raise the child or the relative parenting time of both parties.

New Model- Income Shares

Considers both parents’ relative incomes.
Allocated a prorated share of the expenses to each parent.
Considers the cost of raising a child and the relative parenting time of both parents (in a split or shared situation).

Practitioners should note that the mere change of the law, on July 1, 2017, will not itself constitute a change in circumstances warranting a modification of child support. However, for new cases, or post-decree cases for whom there are other factors present which give rise to a substantial change, and therefore a basis for filing a modification, things to pay attention to under the new statute include: self-employment, multiple family situations, voluntary under-employment or unemployment, outstanding healthcare expenses (for either the parties of the child), and split physical care (i.e. each parent has primary physical possession of at least one child).

To be sure, this new law is a drastic change, but proponents of the law hope that it will give a more equitable distribution of the cost of raising a child. For family law practitioners used to practicing under the old model, this is a paradigmatic change, and careful review of the statute, the new child support calculators and attendance at one or more CLEs is highly recommended.

Masah S. Renwick


The Renwick Firm

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Lashon Smith
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LaShon is M.A.G. senior editor, radio personality hostess, sales consultant, voice actress, and entrepreneur. LaShon has professional experience to include hotel management, social media strategist, narrating and business owner. In her spare time, LaShon likes to craft, and ride motorcycles.