The primary insurance amount (PIA) is the basic figure SSA uses to determine the monthly benefit amount payable to a claimant and his/her family. For example, if someone retires in the month he or she attains full retirement age or if he or she become disabled, he or she will be entitled to a monthly benefit equal to their PIA. If he or she retires prior to full retirement age their monthly benefit will be reduced. Benefits to other members of the family are a specified percentage of the PIA.