Illinois Child Support Calculator (2026)
Illinois calculates child support under income-shares guidelines (750 ILCS 5/505). Estimate the guideline amount below.
Income basis: combined monthly net income of both parents.
Enter the income above to see the guideline estimate.
Simplified guideline estimate, interpolated from the official schedule — before health-insurance, childcare, and parenting-time adjustments. For the exact figure use the official Illinois calculator.
Your Case Details
Answer a few questions to see your estimated range.
Approximate gap between higher-earner and lower-earner.
Estimated Monthly Support
$840 — $1,560
State formulas vary significantly. This estimate uses national averages — your state's guidelines may produce a different number.
Editorially Reviewed — Content reviewed for accuracy using published legal research, government data, and verified court records. See our methodology
Reviewed by Leonard Goldberg, Editor · Last updated
Illinois uses the income-shares model: both parents' incomes are combined, the official schedule sets a basic support obligation, and each parent owes their proportional share (750 ILCS 5/505). The calculator above interpolates the official schedule for a quick estimate — health-insurance, child-care, and parenting-time adjustments come on top.
How Illinois Calculates Child Support
Illinois has used the Income Shares model since July 1, 2017 (Public Act 99-0764), replacing the old percentage-of-obligor-net-income guideline. The court determines each parent's net monthly income (using HFS's standardized Gross to Net Income Conversion Table), adds the two together, looks up the combined figure on HFS's Schedule of Basic Child Support Obligations, and prorates the resulting basic obligation by each parent's percentage share of that combined income. Both the conversion table and the obligation schedule have been revised annually since 2024; the tables currently in force were updated effective March 20, 2026.
Statutory basis: 750 ILCS 5/505. Exact figure: official Illinois calculator.
Official Schedule — Excerpt
Basic support obligation at selected combined incomes (combined monthly net income of both parents), from the official Illinois schedule:
| Combined income | 1 child | 2 children | 3 children |
|---|---|---|---|
| $3,300 | $760 | $1,158 | $1,400 |
| $5,000 | $1,110 | $1,674 | $2,006 |
| $7,500 | $1,370 | $2,035 | $2,397 |
| $10,000 | $1,686 | $2,499 | $2,938 |
Worked Example
Two children, combined net monthly income of $7,500 — custodial parent nets $4,500/month, non-custodial parent nets $3,000/month. On the 2026 Schedule of Basic Child Support Obligations, the row for $7,475.00–$7,524.99 combined net income sets the basic support obligation for 2 children at $2,035/month. The non-custodial parent's income share is $3,000 ÷ $7,500 = 40%, so that parent owes 40% × $2,035 ≈ $814/month, before any add-ons for health insurance premiums, work-related childcare, or extracurricular/school expenses the court allocates separately.
When Courts Deviate From the Guideline
- The child's financial resources and needs
- The parents' financial resources and needs
- The standard of living the child would have enjoyed had the marriage/civil union not been dissolved
- The child's physical and emotional condition and educational needs
- Extraordinary medical expenditures necessary to preserve the life or health of a party or child
- Additional expenses for a child with special medical, physical, or developmental needs
Frequently Asked Questions
Is there a maximum income cap on Illinois child support?
No hard dollar cap exists. The Schedule of Basic Child Support Obligations tops out at $27,374.99 in combined net monthly income; above that, 750 ILCS 5/505 lets the judge use discretion to set an amount, but it cannot be lower than the highest schedule row ($3,547/month for one child, $5,210 for two, $6,069 for three).
What counts as income under Illinois's child support guidelines?
750 ILCS 5/505 defines gross income broadly as the total of all income from all sources — wages, self-employment and business income, bonuses, commissions, and even certain public benefits — which HFS's standardized tax table then converts to net income. Excluded are means-tested benefits like TANF, SSI, and SNAP, plus benefits received for other children in the household, such as child support or foster-care payments already coming in for a different child.
How does 50/50 or shared parenting time change the calculation?
If each parent has the child overnight 146 nights or more per year, Illinois requires a separate 'shared care' calculation: the basic obligation from the schedule is multiplied by 1.5, split between the parents by their income share, then each parent's resulting figure is multiplied by the percentage of time the other parent has the child; the two results are offset, and only one parent pays the difference. A pending 2026 bill (SB 3524) would add a second tier starting at 110 overnights, effective January 1, 2027, but that is not yet law.
Until what age does Illinois child support run, and does it cover college?
Basic child support ends at age 18, or — if the child hasn't graduated high school yet — no earlier than high school graduation or age 19, whichever comes first. College costs are handled separately: under 750 ILCS 5/513, a parent can ask the court to order contribution toward a non-minor child's post-secondary tuition, room and board, and related expenses, but that only happens if it's specifically requested and ordered — it is not an automatic extension of child support.