What is a Handicap Index?
The purpose of the USGA Handicap System is to make the game of golf more enjoyable by enabling players of differing abilities to compete on an equitable basis. The System provides a fair Course Handicap for each player, regardless of ability, and adjusts a player's Handicap Index up or down as the player's game changes. At the same time, the System disregards high scores that bear little relation to the player's potential ability and promotes continuity by making a Handicap Index continuous from one playing season or year to the next. A Handicap Index is useful for all forms of play and is issued only to individuals who are members of an authorized golf club.
A Handicap Index is an attempt to compare a player's scoring ability to the scoring ability of a scratch golfer on a course of standard difficulty. Players post scores along with the appropriate USGA Course Rating, Slope Rating, and date of each score to make up the scoring record. The 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 Differential(s) posted for a given number of rounds, usually the best 8 of the last 20 rounds.
The two most basic assumptions behind the use of the Handicap Index are that
Players will always try to score the best they can
Players will post all scores
Not Your Average
The Handicap Index is not intended to show your average score. It is based on what the USGA projects as your potential ability. By using only the best 8 of your last 20 scores they deliberately set your Index at a level that means you would probably only play to your handicap one out of every 4 or 5 times. If you do it more often, you’re either improving or something is amiss.
You need to remember that because the handicap is based on the best eight of your last twenty scores, even scoring 2 or 3 strokes over that personal par target would be a good score.
What is a course handicap?
For playing purposes, your Handicap is different at each course you play. The Handicap Index is the USGA-defined "portable handicap.” You use the Handicap Index to calculate your Course Handicap for any particular course using the course rating, slope and par for the set of tees you are playing. There is a GHIN application you can download to your phone that will calculate your course handicap for you.