Ohio Rev. Code § 3119.07: Effect of child custody on calculation of child support.

(A) Except when the parents have split parental rights and responsibilities, a parent's child support obligation for a child for whom the parent is the residential parent and legal custodian shall be presumed to be spent on that child and shall not become part of a child support order, and a parent's child support obligation for a child for whom the parent is not the residential parent and legal custodian shall become part of a child support order.

(B) If the parents have split parental rights and responsibilities, the child support obligations of the parents shall be offset, and the parent with the larger child support obligation shall pay the net amount pursuant to the child support order.

(C) If neither parent of a child who is the subject of a child support order is the residential parent and legal custodian of the child and the child resides with a caretaker, each parent shall pay that parent's child support obligation pursuant to the child support order.