1 Child
~20%
2.0pp above average
Data updated September 2026
2026 guideline data Income Shares model OCSE FY2023 source
Illinois Child Support Guidelines
Illinois publishes a 20% one-child starting rate under Income Shares - higher-third among 51 recorded schedules. The Income Shares schedule (43 jurisdictions on this model) opens higher than most peers before deviations.
- 20%
- 1-child base rate
- #4 of 51
- base-rate rank
- #8
- enforcement caseload rank
- 85.1%
- cases with order
$1,203/mo
One-child base rate at Illinois's median income
20% of $72,205, the Census ACS 2022 median household income for Illinois, divided across twelve months, 26% above the median state. An index for comparing states, not a case estimate: guidelines apply to the obligor's income, or to combined parental income under the Income Shares model, and a court sets the actual order. How this is derived.
OCSE guideline posture brief
Illinois Title IV-D posture in this snapshot
Entity-varying stamps from NCSL guideline tables and OCSE FY2023 preliminary reporting (P-52 caseload, P-4 collections, P-64 order share) - not a clone nationwide scaffold.
- 20% published one-child starting rate #4 of 51
- Income 43 jurisdictions share this model
- 85.1% caseload with support order (OCSE P-64) #33 nationally
- 346,651 Title IV-D caseload (OCSE P-52) #8 by volume
- $1,935 distributed collections per case (our calc)
- Alaska nearest rate peer (Δ 0.0 pts)
- 2026 guideline vintage on registry
One-child rate neighbourhood
Published starting percentages among the nearest rate peers (snapshot September 2026).
Income Shares · INC · MID
National context
Where Illinois's one-child starting rate sits
Each bar counts states with a published one-child base rate in that 3-point band. Illinois's higher-third 20% mark is highlighted. Counts are exact from the 51-jurisdiction dataset.
Illinois's 20% published one-child base rate is higher than 42 of 51 recorded state rates. The comparison describes guideline starting percentages, not a complete child-support estimate. Illinois sits in a higher-rate band on this histogram.
Source: State guideline records, 51 jurisdictions with published one-child base rates
2 Children
~30%
4.3pp above average
3 Children
~36%
4.7pp above average
4 Children
~40%
4.8pp above average
Income Cap
None
uncapped
Higher one-child starting rate
Illinois in the higher-rate third
Illinois's published 20% one-child base sits in the higher third (#4 of 51).
Illinois publishes a 20% one-child starting rate under Income Shares - higher-third among 51 recorded schedules. The Income Shares schedule (43 jurisdictions on this model) opens higher than most peers before deviations. Unlike capped states, the formula applies to full reported income before deductions - material on a large caseload. Nearest one-child rate peer: Alaska at 20% (Δ 0.0 pts). Illinois allows a parenting-time adjustment when the non-custodial parent exercises substantial overnight time. A percentage figure alone does not determine the dollar amount - compare Illinois to other guideline models →
On OCSE FY2023 tables, Illinois ranks #33 of 51 on order-establishment share and #8 by caseload volume (~$1,935 distributed per case, our calc on P-4/P-52). Source: HHS Office of Child Support Services, FY 2023 Preliminary Report.
How Illinois Calculates Child Support
Illinois uses the Income Shares model. Both parents' incomes are combined, the total obligation is looked up from a schedule, then split proportionally based on each parent's income share. Its one-child base rate is in line with the national middle range. That higher-third starting rate is the schedule's open before deviations.
Income Shares model since July 1, 2017 (P.A. 99-0764, 750 ILCS 5/505). Both parents' net incomes are combined and the basic obligation is read from the HFS Schedule of Basic Child Support Obligations (effective 2026-03-20), then split by each parent's income share. Parenting time credit at 146+ overnights/year.
Illinois guideline parameters
| Parameter | Value |
|---|---|
| Formula Model | Income Shares |
| Income Floor | None |
| Income Ceiling | Uncapped |
| Parenting Time Adjustment | Available |
| Median Household Income | $72,205/yr |
| Single-Child Base | 20% (rank #4 of 51) |
Not legal advice for Illinois: figures here are published-guideline estimates only. Actual orders can differ under judicial discretion, deviation factors, and the current Illinois schedule. Consult a family law attorney licensed in Illinois.
Illinois Child Support Enforcement
346,651
Active Cases
$670.9M
Annual Collections
85.1%
Cases with Orders
$1,935
Collected per case (our calculation)
Illinois vs national average (51 reporting states)
Cases with orders 85.1%
national
85.1% of Illinois's caseload has a support order established; average across the 51 jurisdictions 86.6%.
Source: HHS Office of Child Support Services, FY 2023 Preliminary Report, Tables P-52 (caseload), P-4 (distributed collections) and P-64 (cases with orders)
D
State Support Program Score
42/100
Illinois
Based on order-establishment rate, per-case collection efficiency, and calculator access from federal OCSE and Census ACS data, not the guideline percentage itself, case outcomes, or any individual family's experience.
Order Establishment F
85.1%
Share of caseload with a support order in place (OCSE Table P-64); 51-state range 80.5%-93.8%, median 86.6%
Collection Efficiency F
$1,935/case
Dollars collected per enforcement case per year (OCSE Table P-4); 51-state range $1,522-$2,922, median $2,131
Income-Adjusted Collections F
2.68% of median income
Collections per case relative to state median household income (OCSE + Census ACS); 51-state range 2.39%-4.24%, median 3.16%
Calculator Access A+
Available
Whether the state publishes an official online support calculator
Calculate Illinois Child Support
Our interactive calculator uses Illinois's formula with your specific income and parenting time inputs.
Open Illinois CalculatorNearest one-child rate peers
Closest published starting percentages to Illinois's 20% (MID band) - model stamps INC/PCT/MEL, not an A-Z clone list.
Read our methodology - how Illinois guideline and OCSE figures on this page are sourced.
Data sources for Illinois
Guideline parameters from Illinois statutes and published schedules; enforcement columns from HHS OCSS FY2023 Preliminary Report (P-52 / P-4 / P-64). See methodology. Retrieved and formatted by PlainChildSupport for Illinois.