StateTally

Illinois Child Support Calculator (2026)

The Illinois Department of Healthcare and Family Services’ 2026 Income Shares Schedule sets child‑support brackets in $50 increments from $25 up to $27,350 of combined monthly net income, with a presumptive $40‑per‑child minimum for low‑income obligors.

Reviewed 2026-09-11 · Estimates only — not legal or financial advice. Figures pending final verification against the current statute/schedule. · Ver esta página en español

The parent who will pay support (usually the one with less parenting time). Monthly net income as the state defines it.
The parent who receives support. Both incomes are added to find the schedule amount.
The law behind this calculator: Illinois income shares schedule of basic child support obligations (combined monthly net income) — 750 ILCS 5/505(a)(1), (3.3a), (3.5); HFS Income Shares Schedule of Basic Child Support Obligations (eff. Mar. 20, 2026).

How Illinois calculates it

  • Add both parents' monthly net incomes to get the combined net income.
  • Find the basic child‑support obligation in the schedule using the combined net income and the exact number of children; the nearest $50 row is used.
  • Multiply the schedule amount by the paying parent's share of the combined income (paying parent income ÷ combined income).
  • If the combined net income exceeds $27,350, the statute adds 0% of the excess for any number of children, so the top‑row figure is the ceiling.
  • When an obligor’s income is at or below 75% of the federal poverty guideline, a presumptive minimum of $40 per month per child (up to $120) applies.
  • Add any child‑care, health‑insurance, and parenting‑time adjustments after the basic amount is calculated.

Worked example

In the worked example, the paying parent earns $4,000 per month net and the other parent earns $2,500 per month net, giving a combined net income of $6,500. The 2026 Illinois schedule shows a basic child‑support obligation of $1,909 for two children at that income level. The paying parent’s share of the combined income is 61.5%, so the basic support owed is 61.5% × $1,909 = $1,175 per month before any child‑care, health‑insurance, or parenting‑time adjustments.

Frequently asked questions

What is the minimum child support amount in Illinois for low‑income parents?

Illinois law sets a presumptive minimum of $40 per month per child (capped at $120 for three children) when the obligor’s income is at or below 75% of the federal poverty guideline.

Does Illinois add any extra percentage for income above $27,350?

No. For combined monthly net income above $27,350 the statute adds 0% of the excess for any number of children, so the top‑row amount is the maximum basic obligation.

How does the number of children affect the basic obligation?

The schedule provides a distinct basic child‑support amount for each income bracket based on the number of children; you look up the row that matches your combined net income and the exact child count.

When was the Illinois child‑support schedule last revised?

The most recent revision took effect on March 20, 2026 and is published by the Department of Healthcare and Family Services.

How does parenting time change the support amount?

If the non‑custodial parent has 146 or more overnights per year, the shared‑physical‑care formula applies, which can reduce the paying parent’s share after the basic amount is calculated.

Is the calculation different in Chicago, Naperville or Lake Forest?

No. 750 ILCS 5/505(a)(1), (3.3a), (3.5); HFS Income Shares Schedule of Basic Child Support Obligations (eff. Mar. 20, 2026) sets one statewide guideline, so a case in Chicago, Naperville, Lake Forest uses the same percentages as anywhere else in Illinois. Judges everywhere in the state may deviate only with written findings.

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Child Support by city in Illinois

Illinois applies one rule statewide, so the numbers do not change by city. These pages name the county court that actually hears the case and run the same verified formula.

Chicago · Aurora · Naperville · Joliet · Rockford · Elgin · Springfield · Peoria · Champaign · Waukegan · Cicero · Bloomington · Schaumburg · Evanston · Arlington Heights · every city we cover

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StateTally. (2026). Illinois Child Support Calculator (2026). Retrieved September 17, 2026, from https://statetally.com/child-support/illinois/