Free · Illinois · Current law
Based on Illinois's official Income Shares formula. Enter both parents' incomes and get an estimate in under a minute.
Before taxes — wages, self-employment, bonuses
A best estimate is fine for now
Taxes, mandatory retirement, union dues…
Work or school related
Estimated monthly support
The other parent pays you, the parent with primary timesharing.
Estimate only — based on a simplified reading of 2025 Income Shares Schedule Based on Net Income, Illinois Department of Healthcare and Family Services. Official calculator → A judge can deviate. Not legal advice.
Get a plain-English copy of this estimate, the numbers used, and a short checklist for what to review before relying on it.
Illinois uses the Income Shares model. The calculation begins by determining each parent's gross monthly income, which is then converted to net income using a standardized conversion chart. These net incomes are combined to establish the total adjusted net income. This combined income, along with the number of children, is used to find the basic child support obligation from the Illinois Income Shares Schedule. Additional expenses such as health insurance premiums, uninsured medical costs, work-related childcare, and extraordinary expenses are added to this basic obligation to determine the total support obligation. Finally, each parent's share of this total obligation is calculated proportionally based on their percentage of the combined net income. For shared parenting (each parent having at least 146 overnights), the basic obligation is multiplied by 1.5, and then each parent's portion is multiplied by the percentage of time the other parent has the child, with the difference paid by the parent with the higher obligation.
A substantial change in either parent's income — voluntary or involuntary — can trigger a modification.
Changes in childcare costs or the children's health insurance premiums directly adjust the support amount.
If the custody schedule changes significantly, support can be recalculated under Illinois guidelines.
Medical conditions, disabilities, or educational needs can justify a departure from the guideline amount.
Common questions
The duration of a divorce in Illinois varies greatly depending on whether it is contested or uncontested, and the complexity of issues like property division and child custody. While there is no mandatory waiting period after filing, cases can take several months to over a year to finalize.
While it is not legally required to have a lawyer for a divorce in Illinois, it is highly recommended, especially if there are complex assets, debts, or child-related issues. A lawyer can ensure your rights are protected and all legal requirements are met.
Yes, Illinois is a pure no-fault divorce state. The only ground for divorce is irreconcilable differences, meaning the marriage has irretrievably broken down (750 ILCS 5/401(a)).
Illinois follows the principle of equitable distribution (750 ILCS 5/503). This means marital property and debts are divided fairly, but not necessarily equally, between the spouses. The court considers various factors to determine a just division.
To file for divorce in Illinois, at least one spouse must have been a resident of the state for a minimum of 90 days immediately preceding the commencement of the action or the making of the finding (750 ILCS 5/401(a)).
We'll match you with a Illinois family law attorney — free, no obligation, no pressure.