Last updated: 3 October 2026
Reviewed by Jordan Morley, FA Level 2 Football Coach
A score differential measures one round's performance relative to the course's difficulty. The formula is (adjusted gross score − course rating) × 113 ÷ slope rating. The 113 is the slope of a course of standard difficulty, so dividing by your course's slope makes differentials comparable between venues. Your Handicap Index is built from your best differentials.
- (Score − course rating) × 113 ÷ slope
- 113 = standard course slope
- Makes rounds comparable across courses
- Best differentials form your index
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A golfer's Score Differential (used in the World Handicap System) adjusts their raw score for both course difficulty (via slope and rating) and playing conditions on that specific day, producing a standardized number that can be fairly compared across rounds played at completely different courses — the best 8 of a golfer's most recent 20 Score Differentials are then averaged to calculate their official Handicap Index.
FAQ
How is Score Differential calculated in golf?
It adjusts a golfer's raw score using that specific course's slope rating and course rating, along with a playing conditions calculation, producing a standardized figure comparable across different courses and days.
How many Score Differentials go into a Handicap Index?
The best 8 Score Differentials from a golfer's most recent 20 rounds are averaged to produce their official Handicap Index under the World Handicap System.