Golf Handicap Calculator · Practical guide
Golf Score Differential Formula
Differential = (Score minus Course Rating) times 113, divided by Slope Rating — one number per round.
At a glance
The Formula
The score differential for any round is (Score − Course Rating) × 113 ÷ Slope Rating. It converts your gross score into a standardized number that accounts for how hard the course played. The calculator above computes a differential for every round you enter.
Interactive tool
Golf Handicap Calculator
Enter your own values, then compare the result with the examples below.
Results
What Each Term Does
- Score − Course Rating: how many strokes over a scratch golfer's expected score you were. Course rating for a typical course is near par, around 70-73.
- 113: the slope rating of a course of standard difficulty. It is the reference point, not a variable you change.
- Slope Rating: ranges from 55 to 155 and measures relative difficulty for bogey golfers. Higher slope means a harder course and a lower differential for the same score.
Worked Examples
| Score | Course Rating | Slope | Differential |
|---|---|---|---|
| 85 | 72.1 | 130 | 11.2 |
| 90 | 72.0 | 113 | 18.0 |
| 90 | 72.0 | 130 | 15.6 |
| 95 | 72.1 | 130 | 19.9 |
From Differentials to Handicap
Your handicap index is the average of your best differentials, rounded to one decimal. The number used depends on how many rounds you have: with 5 rounds only the lowest 1 counts, with 10 the lowest 3, and with a full set of 20 the lowest 8. That best-rounds design is why your index reflects potential rather than average play.
Frequently Asked Questions
Can a score differential be negative?
Yes. Shooting below the course rating produces a negative differential. Scratch and plus-handicap golfers regularly post negative differentials.
Why is 113 used in the formula?
113 is defined as the slope rating of a course with standard difficulty. Multiplying by 113 scales every differential to that baseline so rounds on different courses can be compared fairly.
Where do I find a course's rating and slope?
They are printed on the scorecard and posted near the first tee, listed separately for each set of tees. Always use the values for the tees you played.
Does the formula use my gross or adjusted score?
Official handicaps use adjusted gross score with a maximum of net double bogey per hole. For casual tracking with this calculator, your actual total score works fine.