For many years, Illinois has followed “percentage of payor’s net income” model in calculating child support. This model primarily focused on the non-custodial parent’s income, and oftentimes, did not take into consideration the custodial parent’s income in determining the proper amount of child support. As an example, Illinois courts used a statutory guideline of calculating 20% of the payor’s net take-home pay, as and for child support for one child of the parties.

This will no longer be the case.

After several months of rumors and gossip floating within the family law community of Illinois, an “income share” model for calculation of child support will be made into law effective July 1, 2017, assuming Governor Rauner signs the passed measure into law. Most pundits expect this to happen with little resistance from the Governor’s office.

This new law will follow 39 other states in utilizing the income share model, which shall take into into account both parents’ respective income, expenses, earning capacity, and parenting time.
Although this new law will be effective July 1, 2017, it does not mean that this is an invitation for past litigants to modify their existing orders. A standard of “substantial change of circumstances” will remain the guiding principle for whether an existing child support order can be modified.