Illinois law will calculate child support using shared care and confinement

Courts will calculate shared-care support using each parent's income and time caring for the child. Shared care means each parent provides at least 110 overnight stays per year or approved equivalent care. Significant daytime care can count as equivalent overnight stays if the parents agree or a court allows an exception. Courts multiply basic support by 1.5, divide it by income share, and account for time with the other parent. The parent owing more pays the difference. For 110–145 nights or equivalents, a parent's calculated amount increases by 2%–10%, depending on care time. The adjusted amount cannot exceed ordinary basic support. These provisions take effect January 1, 2027.

A covered parent's support will become $0 if no timely objection is filed or a hearing does not establish grounds to deny the reduction. Coverage requires more than 180 consecutive days of full-time confinement, including home detention. Parole, work release, and other programs allowing earnings are excluded. A party must file notice with the court and notify all parties. Written objections are due within 45 days of the notice's filing-and-mailing date. A timely objection requires a hearing. Evidence of substantial income or available assets, or confinement lasting no more than 180 consecutive days, can defeat the reduction. Parties may seek a different amount based on ability to pay during or after confinement. The reduction applies from the notice's filing-and-mailing date. The required order restarts minimum payments on the first day of the month following 90 days after actual release.

Courts will generally order $40 monthly per child for parents within the low-income threshold, with a $120 monthly total cap. These rules cover parents who owe child support and meet the income or inability-to-work conditions. The threshold is at or below 100% of the federal poverty guideline for one person, using income before taxes or potential earnings counted by the court. The $120 cap is divided equally among all of the paying parent's children. Courts generally order $0 for parents with no income, only income-based public assistance, or an inability to work because of medically proven disability, confinement, or institutional care. Evidence can overcome these default rules. These provisions take effect January 1, 2027.

Child support orders will require both parents to exchange written income information annually. Both parents covered by a child support order must follow its information-sharing requirements. Written information must verify income after taxes and allowed deductions. Reports of new employment must identify the employer's name and address. Failure to report employment changes, together with more than 60 days of unpaid support, is criminal contempt, which can lead to punishment by the court. A court can excuse address disclosure if it would seriously endanger a parent's or child's health. Parents must report job starts or endings to each other and the court clerk within 10 days, and moves to each other within five days.

Courts can apply later child support laws to an existing order only after finding a substantial change in circumstances that warrants it, unless the later law expressly provides otherwise. This rule covers requests to apply later changes to the child support calculation rules to existing support orders. Passing a later law does not itself count as a substantial change in circumstances unless that law expressly says otherwise. This provision takes effect January 1, 2027.