Calculating a Golf Handicap Index
The USGA instituted the golf Handicap Index System in 1911 so golfers with different skill levels can compete with each other on an equitable basis. Golfers can have their Handicap Index calculated at a USGA-licensed golf club using this simple mathematical formula. "Science of Golf" is produced in partnership with the United States Golf Association and Chevron.
DAN HICKS reporting: In the game of golf, it's a commonly-asked question - what's your handicap?
CARTER RICH (Equipment Standards, USGA): My Handicap Index right now is too high at 5.1.
HICKS: A Handicap Index is based on a golfer's ability and the difficulty of the golf course being played. Generally, it refers to the number of strokes a golfer may "take," or subtract, from his or her score.
DREW WEAVER (2007 British Amateur Champion): The neatest part about the game is that my dad and I can go play golf, and I play for a living and he’s a twelve handicap, and we can still enjoy the game at the same capacity.
ERIC LAHMAN (Course Rating & Handicapping, USGA): If you think of someone who’s a scratch golfer, low handicap is zero, versus a bogey golfer, someone who’s around a twenty handicap, they can go out and have a relatively equal match, even though clearly a scratch golfer is a much better player than a bogey golfer.
HICKS: Eric Lahman works for the United States Golf Association, educating golfers about the USGA's Handicap System, which was introduced in 1911 as a way for golfers of differing abilities to play each other on an even basis - and keep it competitive.
LAHMAN: So it doesn’t matter whether you are male or female, tall or short, young or old; we can all compete on an equitable basis.
HICKS: Golfers can have their Handicap Index calculated for them only at golf clubs licensed by the USGA, and all the clubs will use the same simple mathematical equations. Two important factors in the calculations are found on the score card: Course Rating and Slope Rating. The first, Course Rating, is derived from the scores produced by scratch golfers for a set of tees. The second factor, Slope Rating, is found by comparing the Course Rating to the Bogey Rating, which is derived from scores produced by bogey golfers.
LAHMAN: The bogey rating is going to be a higher number than our USGA Course Rating, or for our scratch golfer. And then we draw a line between those two numbers, and the rise over the run of those two points would give us our Slope Rating.
HICKS: Slope Rating indicates the difficulty of a course for the average golfer, where design elements, such as longer fairways or an abundance of trees, can make a course more challenging for a bogey golfer than for a scratch golfer.
LAHMAN: A Handicap Index is a measure of a player’s potential golf ability. Potential ability is a word we use a lot.
HICKS: The Handicap Index formula looks simple, but there's a lot of math built into it. For the first part of the formula, a minimum of 5 scores is required. To calculate a differential for each score, begin with the Adjusted Gross Score - the actual number of strokes a player makes, adjusted per the USGA Handicap System manual. Then subtract the USGA Course Rating; multiply the result by the Standard Slope Rating of 113; then divide by the Slope Rating for the tees being played. With an Adjusted Gross Score of 81, a Course Rating of 71 point 2, and a Slope Rating of 126, the equation would look like this. The answer is rounded to one decimal.
LAHMAN: Every single score a player submits for handicap purposes, it gets put into that handicap differential formula.
HICKS: With only five differentials, find the lowest and put that into the Handicap Index equation. When the number of scores increases, multiple differentials are added together and then divided by the number of differentials to find the average, which is put into the equation.
LAHMAN: The handicap system doesn’t look at an average of all your scores, rather it uses a better-half average of your scores. So, the system looks at when you play well. So that’s why it’s based on potential.
HICKS: The second part of the Handicap Index formula is the number "point 9-6," what the USGA calls the Bonus for Excellence - an incentive for players to improve their games.
LAHMAN: If you think about any number and you take a percentage out of it, it’s going to hit that higher handicap player just a little bit more than it would a lower handicap player. So that’s why we take that ninety-six percent, to smooth it out and make it a little bit more equitable among all the players who have a handicap index.
HICKS: Calculating the formula would look like this. The result is truncated to the nearest tenth. Once the Handicap Index has been calculated, a golfer can find his or her Course Handicap for a specific golf course.
LAHMAN: Near the posting station of a club you’ll generally see Course Handicap tables for converting that Handicap Index to that whole number Course Handicap.
HICKS: Say Player A, with a Course Handicap of 6, makes a 79; and Player B, with a Course Handicap of 15, makes an 87. By subtracting their handicaps from their scores, Player B's 72 beats Player A's 73.
WEAVER: The handicap system that’s in place equalizes the field, it gives everybody, you know, the proper chance to compete even though you don’t have the same skill level.
HICKS: While most golfers couldn't compete with the top golfers stroke for stroke, the Handicap Index is a great way for golfers to understand how they stack up against other players and recognize when they've just played the best round of their lives.