How is a Handicap Index® calculated?

For each score posted, a Score Differential™ is calculated. This is to determine which scores are the best scores, considering the course difficulty (Course Rating™, Slope Rating™,  and a playing conditions calculation are all important). The formula is: 

Score Differential = (adjusted gross score – Course Rating-playing conditions calculation adjustment) x (113 / Slope Rating). 

Using this example: 

  • adjusted gross score was 95 at a course with 73.5/130 (Course Rating/Slope Rating) and no playing conditions calculation adjustment existed
  • adjusted gross score 95
    Minus the Course Rating (73.5)
  • Result = 21.5
  • Use the standard Slope® (113) of a golf course /Slope Rating: 113/130 = .869
  • Multiple 21.5 x .869 = 18.688 Score Differential = 18.7 (rounded to nearest tenth)

Once your score file consists of 20 scores, your eight lowest Score Differentials are added together, averaged and rounded to the nearest tenth, the result being your Handicap Index. Your eight lowest Score Differentials are used, not an average of all your Score Differentials.

A player needs a minimum of three scores to calculate a Handicap Index.