What is a USGA Handicap Index®?

A Handicap Index, issued by a golf club or authorized golf association (through its member clubs), indicates a player’s skill and is a number taken to one decimal place, e.g., 10.4.

A Handicap Index compares a player’s scoring ability to the scoring ability of a scratch golfer on a course of standard difficulty. A player posts scores along with the appropriate USGA Course Rating and Slope Rating to make up the scoring record. A Handicap Index is computed from no more than 20 scores plus any eligible tournament scores. It reflects the player’s potential because it is based upon the best handicap differentials posted for a given number of rounds, ideally the best 10 of the last 20 rounds.

A Handicap Index is portable from course to course, as well as from one set of tees to another set of tees on the same course. A player converts a Handicap Index to a Course Handicap based on the Slope Rating of the tees played.
(2006-2007 USGA Handicap System)