If a claimant begins taking retirement benefits before his full retirement age, the benefit is permanently reduced and the months he received reduced payments are the reduction months. If a claimant opts to receive retirement benefits before his full retirement age, the amount of the benefit will be reduced. The full retirement age depends on when he was born. If the claimant decides to start his benefits early, the reduction will be 5/9 of 1% for every month, up to 36 months early. That works out to 6.67% per year.