Hingham, MA family law attorney James M. Lynch explains how child custody & support is determined in Massachusetts. He explains that child support is determined by both the amount of parenting time each parent has and the paying parent’s ability to contribute. If a child resides with one parent about two-thirds of the time, the other parent is typically required to pay child support, with the amount reflecting the payor’s financial capacity. In a 50/50 parenting arrangement, the higher-earning parent may still pay child support to the lower-earning parent, but the amount is generally less than what would be calculated in a two-thirds/one-third custody split.