Since 2017, Illinois has calculated child support using an “income shares” model. This means Illinois child support is based upon the combined income of both parents. The current model aims to provide children with the standard of living they would have enjoyed if their parents had not divorced or separated. Our current child support law acknowledges the financial contributions and obligations of both parents.

The law includes income from all sources. Maintenance (“alimony”) payments are deducted from the payor’s gross income and added to the payee’s gross income. Other potential adjustments to gross income are certain business and in-kind income.  Voluntary unemployment or underemployment might also be taken into account. After any appropriate adjustments are made to gross income, each parent’s gross income is converted to net income. This is because Illinois uses net income for the child support calculations, not gross income. To determine net income, parents elect either a standardized tax amount or an individualized tax amount.

The child support obligation is divided between the parents pro rata based upon the percentage of their combined income that each earns. The state has created a schedule for basic support obligations based in part on the income levels of parents. This schedule derives from economic data of actual child-rearing expenses from the Bureau of Labor Statistics.

The parent with a majority of parenting time receives the child support. A shared-parenting adjustment is made to child support when each parent has at least 146 overnight stays. In those cases, the basic support obligation is multiplied by 1.5 to reflect the increased child expenses that exist in shared parenting arrangements.

Here is an Illinois Child Support Calculator:  Illinois Child Support Calculator

If you are interested in our services, call Illinois divorce attorney and mediator Tanya Witt at (312) 500-5400 or email This blog does not constitute legal advice. Please consult an attorney about your specific case.