A players Handicap Index is calculated as the average of the best 8 score differentials from the last 20 rounds.
Score Differntial = (Adjusted Gross Score - Course Rating - PCC) * 113/Slope Rating
    
  
| Adjusted Gross Score | The players gross score adjusted so that the score for any hole does not exceed a net double bogey | 
| Course Rating | The course rating for the tees being played | 
| PCC | Playing Conditions Calculation; provides an adjustment if conditions on a day of play differed from normal playing conditions to the extent that they significantly impacted players' performance. | 
| Slope Rating | The slope rating for the tees being played. Note: 113 is the slope rating of a course of standard relative difficulty. | 
    
  
For example: A player has a gross score of 82 when playing from the white tees at KGC. The players course handicap for the round was 10, but they had a gross score of 8 on the 9th hole where they recieve a shot. PCC for the day was 0.
Nett double bogey on the 9th = 4 + 2 + 1 = 7
The players gross is therefore reduced by 1 (8-7) for handicap puposes
Adjusted Gross Score = 82 - 1
Score Differential = (82 - 71.0 - 0) * 113/134= 9.3
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If a player does not have 20 scores their handicap index is calculated as follows:
| Number of Score Differentials in scoring record | Score Differential(s) to be used in calculation of Handicap Index | Adjustment | 
|---|---|---|
| 3 | Lowest 1 | -2.0 | 
| 4 | Lowest 1 | -1.0 | 
| 5 | Lowest 1 | 0 | 
| 6 | Lowest 2 | -1.0 | 
| 7 or 8 | Lowest 2 | 0 | 
| 9 to 11 | Lowest 3 | 0 | 
| 12 to 14 | Lowest 4 | 0 | 
| 15 or 16 | Lowest 5 | 0 | 
| 17 or 18 | Lowest 6 | 0 | 
| 19 | Lowest 7 | 0 | 
| 20 | Lowest 8 | 0 |