Illinois Child Support Calculator

Illinois uses the income shares model, which considers both parents' net income. The court determines a basic support obligation based on the parents' combined net income and the number of children, then divides that obligation proportionally based on each parent's share of the combined income. Parenting time adjustments apply when a parent has 146 or more overnight visits per year.

Net income in Illinois includes all income from all sources (salary, wages, bonuses, commissions, pensions, Social Security, unemployment, rental income, etc.) minus certain deductions: federal and state taxes, Social Security contributions, mandatory retirement contributions, union dues, health insurance premiums for the child, and prior child support or maintenance obligations.

Shared parenting applies when the non-custodial parent has 146 or more overnight visits per year (40% of the time). Under shared parenting, each parent's child support obligation is calculated, multiplied by 1.5, and then adjusted based on the percentage of time the child spends with each parent. The parent with the higher obligation pays the difference to the other parent.

Yes, child support can be modified if there is a substantial change in circumstances, such as a significant change in either parent's income, a change in the child's needs, or a change in parenting time. Either parent can petition the court for a modification. Illinois also allows review every 3 years without requiring a substantial change.

In Illinois, child support typically continues until the child turns 18, or 19 if the child is still in high school. The court may also order support for a non-minor child with a disability. College expenses (called non-minor support or Section 513 contributions) may also be ordered, covering tuition, housing, and other educational costs.

Yes. If the paying parent has fewer than 146 overnights per year, standard support applies. If they have 146 or more overnights (shared parenting), the calculation uses an adjusted formula that accounts for both parents' obligations and the time each parent spends with the child, typically resulting in a lower payment amount.

This calculator provides an estimate based on the Illinois income shares model. Actual child support orders may differ because courts consider additional factors such as childcare costs, healthcare expenses, extraordinary expenses, other children from different relationships, and the specific needs of the child. Always consult with a family law attorney for an accurate assessment.