Estimate Illinois child support under 750 ILCS 5/505 (2026 HFS schedule, eff. Mar. 20, 2026) — Income Shares model, current caps and percentages, with a step-by-step worked example.
| Guideline model | Income Shares |
|---|---|
| Income basis | Net (after-tax) income |
| How it works | Both parents’ incomes are combined, a basic obligation is taken from the state’s official schedule, and each parent pays in proportion to their share of combined income. |
| Caps & limits | Illinois updates its schedule annually - this uses the 2026 schedule (effective March 20, 2026), combined monthly net income bands to ~$26,000; above the top band courts may treat the top amount as a minimum |
| Statute / rule | 750 ILCS 5/505 (2026 HFS schedule, eff. Mar. 20, 2026) |
| Parameters verified | 2026-07 |
Result: $1,336 per month
Illinois uses the income shares model under 750 ILCS 5/505 (2026 HFS schedule, eff. Mar. 20, 2026): both parents’ incomes are combined, a basic obligation is determined, and each parent is responsible for their proportional share. Both parents’ incomes are combined, a basic obligation is taken from the state’s official schedule, and each parent pays in proportion to their share of combined income.
Illinois calculates support on net (after-tax) income as defined in 750 ILCS 5/505 (2026 HFS schedule, eff. Mar. 20, 2026). Illinois updates its schedule annually - this uses the 2026 schedule (effective March 20, 2026), combined monthly net income bands to ~$26,000; above the top band courts may treat the top amount as a minimum.
Yes. The guideline amount under 750 ILCS 5/505 (2026 HFS schedule, eff. Mar. 20, 2026) is presumptive, not absolute - courts may deviate with written findings for factors like extraordinary medical or educational needs, other children supported, or very high income beyond the guideline range.
Apply through the Illinois child support agency or the family court in your county. Existing orders can be modified on a substantial change in circumstances - typically a significant income change, job loss, or a change in custody. The official calculator/worksheet is linked on this page (hfs.illinois.gov).
Estimate only — not legal advice. Based on Illinois guidelines (750 ILCS 5/505 (2026 HFS schedule, eff. Mar. 20, 2026)), last verified 2026-07. Courts may deviate. For an official figure use the official Illinois calculator.