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Illinois Child Support Calculator (2026)

In Illinois, child support is based on both parents' combined income and the number of children. The total is split between you based on how much each parent earns, and parenting time can change the amount. Use the free calculator below for an instant estimate.

How it's calculated
Both parents' income combined
Income used
Take-home pay (after taxes)
Last updated
2025
Verified
2026-05-31

Source: 750 ILCS 5/505 (Illinois Marriage and Dissolution of Marriage Act)

Calculate Your Illinois Child Support

Free estimate — official Illinois guidelines

Your income after taxes and required deductions

How Much Is Child Support in Illinois?

If you make $60,000 a year in Illinois, child support for 1 child is estimated at $903 per month ($10,836 per year). This assumes the other parent earns approximately $36,000/year. Actual amounts depend on both parents' incomes, custody time, and add-on expenses (child care, health insurance).

$1,000/week ($52,000/year): approximately $812/month for 1 child.

Illinois Child Support Estimates by Income (2026)

Annual Income 1 Child 2 Children 3 Children
$40,000/yr $709/mo $1,067/mo $1,274/mo
$50,000/yr $798/mo $1,194/mo $1,418/mo
$60,000/yr $903/mo $1,334/mo $1,564/mo
$70,000/yr $1,005/mo $1,491/mo $1,756/mo
$80,000/yr $1,096/mo $1,613/mo $1,884/mo
$100,000/yr $1,288/mo $1,884/mo $2,182/mo
$120,000/yr $1,476/mo $2,156/mo $2,496/mo

Estimates assume the other parent earns 60% of your income. Actual amounts vary. Compare all states →

How Child Support Is Calculated in Illinois

Factors That Affect Child Support in Illinois

Both parents' monthly net incomes (standardized)
Number of children
Health insurance costs for children
Work-related child care costs
Parenting time (overnights per year)
Other support obligations
Mandatory retirement contributions
Maintenance (alimony) paid or received
Technical details and legal basis

Illinois uses the Income Shares model (750 ILCS 5/505 (Illinois Marriage and Dissolution of Marriage Act)) to calculate child support. This model combines both parents' incomes to determine the total obligation, then divides it proportionally based on each parent's share.

Important Notes for Illinois

  • Illinois switched from the Percentage of Income model to the Income Shares model effective July 1, 2017.
  • Child support is based on both parents' combined monthly net incomes using standardized tax deduction tables.
  • Net income is calculated using a standardized tax chart rather than actual taxes, ensuring consistency.
  • Illinois provides a shared parenting time adjustment when the non-custodial parent has 146 or more overnights per year (40%).

Example Calculation

Scenario: Parent A earns $5,000/month, Parent B earns $3,000/month, 2 children.

Step 1: Combined income: $8,000

Step 2: Parent A's share: $5,000 / $8,000 = 62.5%

Step 3: Look up basic obligation for $8,000 combined and 2 children.

Step 4: Multiply by Parent A's share (62.5%).

Adjustments for health insurance, child care, and parenting time may apply.

Key Facts: Child Support in Illinois

  • Illinois uses the Income Shares model (since July 1, 2017), basing child support on both parents' combined monthly net incomes.
  • Net income is calculated using standardized tax deduction tables rather than actual tax returns.
  • The basic obligation for 1 child ranges from $207/month at $875 combined income to $3,463/month at $26,675 combined monthly net income (2025 HFS schedule).
  • A shared parenting adjustment applies when the non-custodial parent has 146 or more overnights per year (40% of the time).
  • The self-support reserve is 75% of the federal poverty level, approximately $998 per month (2026 FPL).

Illinois Child Support FAQ

How is child support calculated in Illinois?
Illinois uses the Income Shares model under 750 ILCS 5/505. Both parents' monthly net incomes are combined, and a basic child support obligation is looked up in the guidelines schedule. Each parent pays their proportional share based on their percentage of the combined net income. Illinois switched to this model from a flat percentage model on July 1, 2017.
How much is child support in Illinois?
Child support in Illinois depends on both parents' combined net income and the number of children. For 1 child at $4,975 combined monthly net income, the basic obligation is approximately $1,097. At $9,975 combined, it's approximately $1,674. The non-custodial parent pays their proportional share (2025 HFS schedule).
How is net income calculated for Illinois child support?
Illinois uses a standardized tax chart rather than actual tax returns to calculate net income. Gross income minus standardized federal and state taxes, FICA, mandatory retirement contributions, existing support obligations, and maintenance (alimony) payments gives the net income used in the guidelines.
Does shared parenting reduce child support in Illinois?
Yes. Illinois applies a "shared parenting" adjustment when the non-custodial parent has 146 or more overnights per year (40% of the time). Under this adjustment, each parent's child support obligation is calculated separately, and the difference between the two is the amount paid by the higher-earning parent.
Is this Illinois child support calculator updated for 2026?
Yes. This calculator uses the 2025 Illinois HFS Income Shares Schedule, effective March 5, 2025, under 750 ILCS 5/505. We last verified every schedule figure against the official Illinois HFS source on May 31, 2026.
How much is child support for 2 kids in Illinois?
For 2 children in Illinois, the basic obligation at $4,975/month combined net income is $1,655. At $9,975/month, it's $2,477. The non-custodial parent's actual payment is their proportional share of this amount based on their percentage of the combined net income.
Does this Illinois calculator include alimony or spousal support?
This calculator estimates child support only, not alimony. Illinois net income calculations do account for maintenance (alimony) already being paid or received, which can affect the income figures used for child support, but the alimony amount itself is decided separately by the court using different factors.
What factors determine child support in Illinois?
Illinois child support is based on both parents' standardized monthly net incomes and the number of children, using the Income Shares model. Courts also factor in health insurance and work-related child care costs, parenting time (overnights per year), other support obligations, mandatory retirement contributions, and maintenance (alimony) paid or received.

About This Calculator

Uses the official 750 ILCS 5/505 (Illinois Marriage and Dissolution of Marriage Act) (2025 guidelines). Last verified: 2026-05-31.

Disclaimer: Estimates only, not legal advice. Actual amounts are set by Illinois courts. Full disclaimer.

Methodology: Income Shares model per 750 ILCS 5/505 (Illinois Marriage and Dissolution of Marriage Act).

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