Last verified: February 2026
Illinois uses the Income Shares Model to calculate child support, considering both parents’ incomes to ensure children receive fair financial support from each parent. This guide explains how Illinois calculates child support, recent changes to the law, modification procedures, and enforcement methods.
Quick Summary: Illinois Child Support
- Model Used: Income Shares Model (since July 1, 2017)
- Age of Termination: 18 years old (or 19 if still in high school)
- Governing Law: 750 ILCS 5/505 (Illinois Marriage and Dissolution of Marriage Act)
- Recent Update: Income tables updated March 5, 2025
- Review Cycle: Guidelines reviewed every 4 years (next review: 2026)
If after reading this you have further questions and would like a consultation, you can get a free case consultation from a lawyer here.
Table Of Contents
- Overview of Illinois Child Support Guidelines
- How Child Support Is Calculated in Illinois
- What Counts as Income in Illinois
- Recent Changes to Illinois Child Support Laws
- How to Modify Child Support in Illinois
- Enforcement of Child Support Orders
- When Child Support Ends in Illinois
- Frequently Asked Questions
Overview of Illinois Child Support Guidelines
Illinois adopted the Income Shares Model on July 1, 2017, replacing the previous “Percentage of Non-Custodial Parent Income” method. Under this model, child support is based on the adjusted net income of both parents, ensuring children receive the same proportion of parental income they would have received if the family remained intact.
The Illinois Department of Healthcare and Family Services (HFS) establishes child support guidelines that include worksheets and schedules for calculating support obligations. These guidelines are regularly reviewed through a federally mandated quadrennial review process to ensure calculations remain fair and reflective of current economic conditions.
How Child Support Is Calculated in Illinois
Under 750 ILCS 5/505, Illinois courts calculate child support using the following steps:
- Determine each parent’s monthly net income
- Add the parents’ monthly net incomes together to get combined monthly net income
- Select the appropriate amount from the Schedule of Basic Child Support Obligations based on combined income and number of children
- Calculate each parent’s percentage share of the basic child support obligation
To estimate your child support obligation, use the official Illinois Child Support Estimator.
Example Calculation
If Parent A has a monthly net income of $4,000 and Parent B has a monthly net income of $2,000:
- Combined monthly net income: $6,000
- Parent A’s share: 67% ($4,000 / $6,000)
- Parent B’s share: 33% ($2,000 / $6,000)
The Schedule of Basic Support Obligations would show the total support amount for two parents with $6,000 combined income and the number of children. Each parent’s share is then calculated based on their percentage of combined income.
What Counts as Income in Illinois
Illinois uses “net income” for child support calculations. Net income is gross income minus specific deductions.
Gross Income Includes:
- Salaries, wages, tips, and commissions
- Bonuses and overtime pay
- Self-employment income
- Interest and dividend income
- Rental income
- Pension and retirement benefits
- Social Security benefits
- Unemployment and workers’ compensation benefits
- Disability benefits
- Spousal maintenance received
Excluded from Gross Income:
- Public assistance benefits (TANF, SNAP, etc.)
- Income and benefits received for other children
- Child support received for children from another relationship
Deductions to Arrive at Net Income:
- Federal and state income taxes (based on proper withholding)
- FICA (Social Security and Medicare taxes)
- Mandatory retirement contributions
- Union dues
- Health insurance premiums for the parent
- Prior child support obligations
- Spousal maintenance paid
Imputed Income
If a parent is voluntarily unemployed or underemployed, the court may impute income based on that parent’s earning capacity. The court considers work history, qualifications, job opportunities, and earnings levels in the community.
Recent Changes to Illinois Child Support Laws
Illinois has made several updates to child support guidelines in recent years:
2024-2025 Updates
- March 5, 2025: Both the Gross to Net Income Conversion Table and the Income Shares Schedule of Basic Child Support Obligations were revised with new amounts
- Since 2024: Illinois annually updates both tables (previously only the Gross to Net table was updated yearly)
- The 2024 regulations updated how childcare costs are divided between parents using the income shares model
2022 Quadrennial Review
The most recent comprehensive review was completed in 2022 and produced the Illinois Child Support Guidelines Quadrennial Review Report. The next quadrennial review will be completed in 2026.
For the most current tables and schedules, visit the HFS Income Shares page.
How to Modify Child Support in Illinois
Illinois allows modification of child support orders under specific circumstances. The process depends on what type of order you have:
Types of Modifications
- DCSS Health Care Modifications: Call 1-800-447-4278
- Judicial Orders: Modified through the courts
- Administrative Orders: Modified through Health Care and Family Services
Conditions for Modification
To qualify for a child support modification in Illinois:
- A substantial change in circumstances has occurred (involuntary unemployment, disability, incarceration)
- At least three years have passed since the order was established, modified, or reviewed
- Either parent submits a written request for review
If one parent experiences a substantial increase in income and fails to disclose it, the other parent can request back support retroactively.
Important: The court may deny a modification request if it finds that a parent is voluntarily unemployed or underemployed to reduce their support obligation.
Enforcement of Child Support Orders
Illinois takes child support enforcement seriously. Apply for enforcement services or check amounts owed here.
Enforcement Methods
- Income Withholding: Automatic payroll deductions
- Bank Account Garnishment: Seizure of funds
- License Suspension: Driver’s, professional, and recreational licenses
- Property Liens: Against real estate and personal property
- Tax Refund Intercept: State and federal refunds
- Passport Denial/Revocation: If arrears exceed $2,500
- Credit Bureau Reporting: Affecting credit scores and lending ability
“Deadbeat” Program
If back support exceeds $5,000, Illinois Public Aid Code 305 ILCS 5/12-12.1 allows the state to publicly list delinquent parents on the “most wanted child support offenders” list.
Criminal Penalties
- Arrearage over $5,000: Class A misdemeanor (up to 1 year in jail)
- Leaving state to evade support: Class 4 felony
- Arrearage over $20,000 or failure to pay for 1+ year: Class 4 felony (1-3 years in prison)
Debt Forgiveness Program
Illinois offers a debt forgiveness program that can permanently remove past-due payments owed to the state. Qualifying conditions include disability, incarceration, or involuntary job loss. Call 1-800-447-4278 for more information.
When Child Support Ends in Illinois
Child support in Illinois normally terminates when the child reaches age 18. However, support may continue or end earlier depending on circumstances:
Support May Continue Beyond 18 If:
- The child is still in high school (support continues until 19 or graduation, whichever comes first)
- The child has special needs requiring ongoing support
- Parents agree in writing to continue support (such as for college expenses)
Support May End Before 18 Through:
Emancipation
A child 16 or older may petition for emancipation if they can demonstrate financial independence and the ability to live independently. Emancipation legally terminates parental support obligations.
Marriage
Minors over 16 can legally marry with parental permission in Illinois, which terminates parental obligations.
Military Service
Joining the armed forces with parental consent (for those under 18) terminates the support obligation.
Termination of Parental Rights
The state, not the parent, must prove the parent is unfit for a judge to terminate parental rights. A parent cannot simply sign away rights to avoid child support obligations.
Frequently Asked Questions
Do you have to pay child support if you have joint custody in Illinois?
Yes. Even with joint custody, the higher-earning parent typically pays support to ensure the child enjoys a consistent standard of living in both homes. The Income Shares Model accounts for both parents’ incomes regardless of custody arrangement.
How do I contact the Division of Child Support Services?
Call 1-800-447-4278 or visit the DCSS website.
What if my ex-spouse refuses to pay child support?
Report non-payment to DCSS. The state has extensive enforcement tools including wage garnishment, license suspension, and criminal prosecution for persistent non-payment.
Can child support be modified if I lose my job?
Yes, involuntary job loss is considered a substantial change in circumstances. However, you must petition for modification promptly. Support obligations continue at the original amount until officially modified by the court.
Does Illinois consider a new spouse’s income for child support?
Generally, no. A new spouse’s income is not directly included in child support calculations. However, if a new spouse’s contributions significantly change your financial situation, it could indirectly affect a modification request.
If you require the assistance of an attorney familiar with Illinois Family Law you can get a free consultation with a lawyer here.
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