Illinois Child Support Calculator
Estimate child support under 750 ILCS 5/505 (Illinois Marriage and Dissolution of Marriage Act). Calculate baseline support, parenting time overnights, health insurance credits, and work-related childcare costs.
1. Enter Case Information
IL RulesEstimated Child Support
IL EstimateUnderstanding Illinois Child Support Guidelines
Illinois calculates support using an Income Shares model under 750 ILCS 5/505. Net income is converted from gross income using either a standardized tax table or individualized tax calculations.
Shared Custody & Overnights in Illinois
Under 750 ILCS 5/505(a)(3.8), when each parent exercises at least 146 overnights per year (40%), shared physical care applies. Basic support is multiplied by 1.5 and allocated based on percentage of time.
Calculate Your Exact Overnights →Official Court Worksheets & Forms
Family court filings in Illinois require completing: Illinois Department of Healthcare and Family Services (HFS) Child Support Worksheet. Review official forms before filing.
View State Worksheets Directory →Worked Calculation Example: Standard Illinois Scenario
Here is a realistic line-by-line computation for two parents in Illinois raising 2 children:
| Guideline Worksheet Line Item | Parent A (Paying) | Parent B (Receiving) | Combined / Order Total |
|---|---|---|---|
| Monthly Guideline Income | $5600 | $3900 | $9500 |
| Parental Income Proportion | 59% | 41% | 100% |
| Basic Child Support Schedule Obligation | - | - | $1580 /mo |
| Work-Related Childcare Cost | - | - | +$450 /mo |
| Health & Dental Insurance Premium | - | - | +$220 /mo |
| Total Combined Child Financial Needs | - | - | $2250 /mo |
| Final Estimated Monthly Support Order | Paid by Parent A to Parent B | $1240 /month | |
Frequently Asked Questions in Illinois
Key legal questions regarding child support establishment, modifications, and enforcement in Illinois.
What is the 146 overnight rule in Illinois?
In Illinois, shared physical care is defined as each parent having the child for at least 146 overnights (40% of the year). This triggers the 1.5x shared physical care multiplier.
What is the difference between standardized and individualized tax calculations in Illinois?
Illinois offers a "Standardized Tax Amount" based on standard IRS tables and single filing status, or an "Individualized Tax Amount" based on actual federal and state tax returns and itemized deductions.
How does Illinois calculate support for college expenses?
College educational expenses in Illinois are governed separately under 750 ILCS 5/513, evaluated based on financial resources of both parents and the student.
Next Useful Steps for Your Case
Take the next step in preparing your family financial documentation:
Convert Irregular Income
Standardize hourly wages, seasonal overtime, or commissions into monthly gross figures.
Launch Income Tool →Explore 50/50 Custody
See how equal time sharing and reciprocal guidelines impact final transfer payments.
50/50 Custody Tool →Download Official Worksheets
Find the exact PDF court forms and financial affidavits required by your court clerk.
Court Worksheets Directory →