Model Illinois Child Support & Spousal Maintenance
Our calculators follow 750 ILCS 5/505 Income Shares, the shared parenting cross-credit, and the 33⅓%–25% maintenance test so attorneys, mediators, and families can benchmark guideline outcomes within minutes.
We follow the HFS schedule placeholder and shared-care multiplier, showing how maintenance feeds the child support calculation.
Go to Child Support CalculatorSee whether guidelines apply, the projected monthly amount, and how it adjusts child support inputs.
Go to Maintenance CalculatorKey Statutory Highlights
750 ILCS 5/505 requires Income Shares with a 1.5 multiplier and cross-credit when each parent has ≥146 overnights.
Maintenance guidelines apply only when combined gross income is under $500,000 and the payor has no prior support obligations.
Guideline maintenance must leave the payee with no more than 40% of combined net income (750 ILCS 5/504).
Orders may be reduced to protect an obligor’s minimum net income using poverty-level benchmarks from HFS guidance.
Childcare, insurance, and extraordinary expenses are prorated by income share with reimbursements built into the transfer.
Statutory factors increase from 0.20 to 0.80 as the marriage length moves from 5 to 20 years.
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Frequently Asked Questions
Illinois multiplies the combined monthly net income by a Basic Child Support Obligation from the HFS schedule, then prorates the award based on each parent’s income share. Shared parenting (≥146 overnights each) adds a 1.5 multiplier and cross-credit calculation.
When guidelines apply, maintenance equals 33⅓% of the payor’s net income minus 25% of the payee’s net income, capped so the payee receives no more than 40% of the combined net income. The formula is available when combined gross income is under $500,000 and the payor has no prior support orders.
Multiply the length of the marriage by the statutory factor in 750 ILCS 5/504(b-1)(1)(B). For example, 10 years × 0.44 = 52.8 months. Marriages of 20+ years may result in maintenance equal to the length of the marriage or indefinite duration.
Yes. Work-related childcare, children’s health insurance, and approved extraordinary expenses are allocated between the parents according to their income shares and added to (or subtracted from) the monthly transfer amount.
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Stay Current with Illinois Income Shares
When HFS releases updated schedules or the legislature amends 750 ILCS 5/504-505, we refresh our calculators so you can negotiate from the same baseline the courts use.