Effective July 1, 2017, Illinois moved from calculating child support as a flat percentage of the payor’s net income based on the number of minor children to an "Income Shares” model under which child support is determined based upon the combined income of both parents and the number of minor children, then divided amongst the parents based upon their respective share of the total income. To put it simply, the more total income the two parents have, the more the combined child support obligation will be and the split of that obligation between the two parents will be proportional to their respective incomes. For example, if the total child support obligation is $2,000 and the parent who the children live with primarily earns 40%% of the combined income, then the payor’s child support payment to the recipient will be $1,200 ($2,000 x 60%%). There are further complexities to the calculation such as an adjustment to the formula for parents with equal or nearly equal parenting time, a factoring of the cost of the children’s health insurance, and alternate approaches to the adjustment from gross income to after-tax net income. It is important to work with an experienced family law attorney with training and experience in implementing the new Illinois child support law.