Amends the Illinois Marriage and Dissolution of Marriage Act. Provides for a child support calculation for shared physical care in which each parent exercises 110 or more overnights per year with the child or 110 or more overnight equivalents as determined by a court as a deviation from guidelines or upon agreement by the parties. Provides that overnight equivalents are calculated by using a method other than overnights if the parent has significant parenting time periods on separate days in which the child is in the parent's physical care and under the direct care of that parent but does not stay overnight. Provides that if parents have shared physical care of a child, the basic child support obligation is multiplied by 1.5 to calculate the combined shared care child support obligation; the court shall determine each parent's portion of the shared care child support obligation based on the parent's percentage share of combined adjusted net income; the shared care child support obligation is then computed for each parent by multiplying that parent's portion of the shared care support obligation by the percentage of time the child spends with the other parent and determining any adjustment for shared physical custody that is less than 146 overnights or overnight equivalents. Provides that the respective shared care child support obligations are then offset with the parent owing more paying the difference in child support. Creates a statutory table to calculate the child support if a parent has physical shared custody for less than 146 overnights or overnight equivalents per year. Provides that the shared care child support obligation after adjustment may not be greater than the amount that would have been ordered under the basic support guidelines in any event. Provides that a parent incarcerated for more than 180 days is presumed to be unable to pay any amount of child support, and this presumption may be rebutted by evidence establishing the ability to pay child support during incarceration. Provides a rebuttable presumption that a minimum child support obligation of $40 per month, per child, will be entered for an obligor who has actual or imputed gross income at or less than 100% of the most recent United States Department of Health and Human Services Federal Poverty Guidelines for a family of one person.