Oh, you're hardcore: You want to know the math behind the golf handicap calculation. OK, you got it. Here's the handicap formula explained. The handicap is used to determine on which holes a player (or team) is granted extra strokes. These are then used to. A minimum of five scores and a maximum of 20 is required to get started. For each score, the USGA Course Rating and Slope Rating for the courses played are.