Illinois Child Support Guidelines
Estimate Illinois Child Support
This calculator uses the 2026 Illinois HFS Income Shares materials and the framework in 750 ILCS 5/505. It also recognizes the shared-care changes in Public Act 104-0733 that take effect January 1, 2027.
Enter each parent's gross income, the number of children, parenting overnights, and the calculation date. Optional child-care, health-insurance, and prior court-ordered support adjustments can be added below.
How to use this calculator
- Enter each parent's annual gross income and the number of children covered by the same support calculation.
- Enter Parent A's annual overnights. Parent B's overnights are calculated automatically so the total is 365.
- Choose the calculation or anticipated order date. The calculator applies the current 146-overnight shared-care threshold through December 31, 2026 and the enacted 2027 framework beginning January 1, 2027.
- The standard method estimates net income using the 2026 HFS gross-to-net conversion. An advanced option allows individualized net income and prior court-ordered support adjustments.
- Tell the calculator whether maintenance is being paid between the parents and enter the monthly amount. If you are not sure whether maintenance applies or do not know the amount, open our Illinois Maintenance Calculator in a new tab.
- Add work-related child care and the child-attributable health-insurance premium if you want those expenses included in the estimate.
This tool assumes all children in the calculation follow the same parenting schedule. It does not automatically calculate split physical care, overnight equivalents, imputed income, non-court-ordered multi-family adjustments, deviations, or extraordinary expenses. The maintenance adjustment assumes the current post-2018 federal tax treatment; legacy tax-deductible maintenance requires an individualized calculation.
Child Support Estimator
* indicates a required field. Income figures are annual unless a field specifically says monthly.
$
Annual gross income from applicable sources.
Enter a valid annual gross income.
$
Annual gross income from applicable sources.
Enter a valid annual gross income.
The published HFS schedule lists obligations for one through six children.
Select the number of children.
Used to determine whether the current rules or the January 1, 2027 changes apply.
Enter a valid calculation date.
Use actual annual overnights. The 2027 statute may also recognize court-approved or agreed overnight equivalents; this calculator does not estimate them.
Enter a whole number from 0 through 365.
Automatically calculated as 365 minus Parent A's overnights.
The standardized method estimates monthly net income from the 2026 HFS gross-to-net framework. Individualized statutory net income may differ.
The HFS standardized tax conversion uses different dependency assumptions for the majority-parent and non-majority-parent columns. The automatic option uses the parent with more annual overnights; choose an override if the applicable tax/dependency treatment is different.
Choose a treatment or use individualized net income.
For current post-2018 maintenance, Illinois child-support calculations generally deduct maintenance from the payor's after-tax income and add it to the recipient's net income. Not sure? Open our Maintenance Calculator in a new tab.
Choose a maintenance treatment. If you are unsure, use the Maintenance Calculator first.
$
Enter the monthly maintenance actually paid or payable between Parent A and Parent B. Leave at $0 if no maintenance is being paid.
Enter a maintenance amount greater than $0 when a payor/recipient direction is selected.
$
Annual statutory net income before the optional prior-support adjustment below.
Enter a valid annual net income not greater than gross income.
$
Annual statutory net income before the optional prior-support adjustment below.
Enter a valid annual net income not greater than gross income.
Advanced adjustments and child-related expenses (optional)
$
Monthly child support actually paid under a court order for children of another relationship. Do not enter support from this case.
$
Monthly child support actually paid under a court order for children of another relationship.
$
Monthly reasonable child-care expense. If an applicable child-care tax credit is known, use the net expense after that credit.
Select the parent who pays this expense.
$
Monthly premium attributable to the child or children in this case, not the full family premium.
Select the parent who pays this expense.
Estimated Illinois Child Support
Estimated Monthly Transfer$0.00
Direction—
Parenting-Time Method—
Parent A Monthly Net Used$0.00
Parent B Monthly Net Used$0.00
HFS Basic Support Obligation$0.00
| Parent A monthly net before maintenance/prior support | — |
|---|---|
| Parent B monthly net before maintenance/prior support | — |
| Maintenance adjustment | — |
| Parent A adjusted monthly net | — |
| Parent B adjusted monthly net | — |
| Combined adjusted monthly net | — |
| Parent A income share | — |
| Parent B income share | — |
| Base child-support transfer before selected expenses | — |
| Child-care allocation adjustment | — |
| Health-insurance allocation adjustment | — |
Important: This calculator is an educational estimate, not legal advice or a prediction of a court order. The maintenance feature assumes the current post-2018 federal tax treatment and adjusts the parents' net incomes for maintenance paid/payable between them; legacy tax-deductible maintenance requires an individualized calculation. Illinois child support can also involve individualized net income, multi-family adjustments, deviations, split physical care, extraordinary expenses, imputed income, minimum-support or zero-order provisions, and other facts not fully modeled here. For calculations dated January 1, 2027 or later, the tool applies the enacted statutory shared-care changes using the current 2026 HFS income tables; an updated HFS 2027 worksheet or income schedule may change the result.
Sources: 750 ILCS 5/505; Illinois HFS Income Shares; 2026 HFS Schedule of Basic Child Support Obligations; 2026 HFS Gross-to-Net Conversion Table; Public Act 104-0733 / SB 3524.
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