A golf handicap is the game's great equalizer.
With a certified handicap you have a fair chance to win a net score match against a superior player. The first step to acquiring an official handicap under the United State Golf Association system is to establish a handicap index. You must establish your index at a club that’s certified to use the USGA’s handicap system.
Index
The handicap index is "a measurement of a player's potential ability on a course of standard playing difficulty," according to the USGA. The golfer uses the handicap index to determine his handicap at a particular course, based on the difficulty of that course.
The golfer can receive a handicap index after posting five scores, but the handicap will eventually be based on 20 rounds.
Because a handicap is designed to measure a player’s peak ability, rather than his average play, his index is calculated by using the 10 best of his 20 most recent scores. The handicap service to which the club subscribes -- such as the USGA's GHIN service or GolfNet -- calculates the golfer's handicap index using a complex formula.
The maximum handicap index is 36.4 for a man, 40.4 for a woman. Handicap indexes are typically updated every two weeks.
Course Ratings
A player’s handicap index can be adapted to any course that has a USGA rating. Courses are rated in two ways. The course rating indicates the typical number of strokes a scratch golfer – generally meaning a zero handicap player – will take under normal conditions. Typically, courses have ratings from the high 60s to the middle 70s.
The course’s slope rating measures a course’s difficulty relative to a “bogey player” -- someone who will carry a course handicap of 20 on a course of standard difficulty.
The lowest possible slope rating, which is given to the easiest courses, is 55, while the highest is 155.
A course of average difficulty carries a slope rating of 113. For example, California's famed Pebble Beach Golf Links has a course rating of 75.5 and a slope rating of 145 from the back tees.
Course Handicap
A handicap index is translated into a course handicap by employing another USGA formula.
To make it easy, clubs generally post a chart – based on the course’s slope rating – that translates a player’s handicap index into her actual handicap for that particular course. The USGA also provides an online course handicap calculator.
Handicap Index Translated
If a golfer with a handicap index of 10.0 plays a course with a slope rating of 100, his course handicap is 9. The handicap goes down because the course is slightly easier than average.
If the same golfer plays a course rated 125, however, his course handicap rises to 11. The course handicap is always expressed as a whole number.