Child support is determined with the use of a formula in Illinois. The amount of money a parent is ordered to provide for child support is directly tied to the parent's income and number of children. For example, a parent in Illinois would typically be ordered to pay 20 percent of his or her net income to support one child and 28 percent to support two children. However, the child support formula is a guideline rather than a hard and fast rule.
When parents make the decision to divorce, emotions run high as factors related to child custody are decided. In most cases, the spouse who retains primary custody of a child is granted child support. Several states, including Illinois, calculate child support amounts based on a payee's income and the number of children he or she has.