How to Calculate a Golf Handicap (World Handicap System)
By Erdi Doğan, owner and editor ·
To calculate a golf handicap under the World Handicap System, turn each round into a Score Differential with the formula (113 ÷ Slope Rating) × (adjusted gross score − Course Rating), then average the lowest 8 of your most recent 20 differentials and round to one decimal. That average is your Handicap Index. Before a round you convert it into strokes for the tees you play: Handicap Index × Slope ÷ 113 + (Course Rating − Par). Below is the full method with a 20-round worked example. For the bigger picture, see the guide to golf handicaps; to skip the arithmetic, use the handicap calculator.
Step 1: Adjust each score to net double bogey
Your handicap is meant to reflect your potential, so one blow-up hole should not distort it. For handicap purposes the most you can score on any hole is net double bogey: par + 2 + the handicap strokes you receive on that hole (Rule 3.1). If you receive one stroke on a par 4, any score above 7 counts as 7. The total after these caps is your adjusted gross score. If you post hole by hole in the GHIN app, it applies the cap for you.
New golfers without an index use par + 5 as the maximum on each hole until they have one.
Step 2: Turn each round into a Score Differential
Score Differential = (113 ÷ Slope Rating) × (Adjusted Gross Score − Course Rating − PCC)
Course Rating and Slope Rating are printed on the scorecard for each set of tees. Course Rating is what a scratch golfer is expected to shoot from those tees; Slope Rating, from 55 to 155, shows how much harder the course is for a bogey golfer, with 113 as the standard. PCC is the playing conditions calculation, a daily adjustment of −1 to +3 that the system applies when scores across the field come in unusually high or low. It is usually 0.
Example: a 94 on tees rated 71.8 with a Slope of 130. 94 − 71.8 = 22.2. 113 ÷ 130 = 0.869. 0.869 × 22.2 = 19.3. The differential is 19.3, rounded to the nearest tenth (Rule 5.1).
Step 3: Average the lowest 8 of the last 20
Here are 20 rounds over three courses. The eight lowest differentials, marked ✓, are the ones that count.
| Round | Adjusted score | Course Rating | Slope | Differential |
|---|---|---|---|---|
| 1 | 94 | 71.8 | 130 | 19.3 |
| 2 | 89 | 70.6 | 125 | 16.6 ✓ |
| 3 | 97 | 72.4 | 133 | 20.9 |
| 4 | 91 | 71.8 | 130 | 16.7 |
| 5 | 86 | 69.9 | 122 | 14.9 ✓ |
| 6 | 93 | 70.6 | 125 | 20.2 |
| 7 | 88 | 71.8 | 130 | 14.1 ✓ |
| 8 | 95 | 72.4 | 133 | 19.2 |
| 9 | 90 | 69.9 | 122 | 18.6 |
| 10 | 92 | 71.8 | 130 | 17.6 |
| 11 | 87 | 70.6 | 125 | 14.8 ✓ |
| 12 | 96 | 72.4 | 133 | 20.1 |
| 13 | 89 | 71.8 | 130 | 15.0 ✓ |
| 14 | 91 | 69.9 | 122 | 19.5 |
| 15 | 85 | 70.6 | 125 | 13.0 ✓ |
| 16 | 94 | 71.8 | 130 | 19.3 |
| 17 | 90 | 72.4 | 133 | 15.0 ✓ |
| 18 | 88 | 69.9 | 122 | 16.8 |
| 19 | 93 | 70.6 | 125 | 20.2 |
| 20 | 89 | 71.8 | 130 | 15.0 ✓ |
The lowest eight are 13.0, 14.1, 14.8, 14.9, 15.0, 15.0, 15.0 and 16.6. They add up to 118.4, and 118.4 ÷ 8 = 14.8. This golfer's Handicap Index is 14.8. The other twelve rounds still matter: when a new round is posted, the oldest drops out and the lowest eight are picked again from the new set of 20 (Rule 5.2b).
If you have fewer than 20 scores
You need at least 54 holes, such as three 18-hole rounds, for a first index. With fewer than 20 scores, Rule 5.2a uses fewer differentials and, for the smallest records, a small adjustment:
| Scores | Differentials used | Adjustment |
|---|---|---|
| 3 | Lowest 1 | −2.0 |
| 4 | Lowest 1 | −1.0 |
| 5 | Lowest 1 | 0 |
| 6 | Average of lowest 2 | −1.0 |
| 7 or 8 | Average of lowest 2 | 0 |
| 9 to 11 | Average of lowest 3 | 0 |
| 12 to 14 | Average of lowest 4 | 0 |
| 15 or 16 | Average of lowest 5 | 0 |
| 17 or 18 | Average of lowest 6 | 0 |
| 19 | Average of lowest 7 | 0 |
| 20 | Average of lowest 8 | 0 |
No Handicap Index can be higher than 54.0.
Step 4: Convert the index to a Course Handicap
Course Handicap = Handicap Index × (Slope Rating ÷ 113) + (Course Rating − Par)
Our golfer with a 14.8 index plays tees rated 71.8, Slope 130, par 72: 14.8 × 130 ÷ 113 = 17.03, plus (71.8 − 72) = −0.2, gives 16.83, which rounds to a Course Handicap of 17 (Rule 6.1). In individual stroke play the recommended allowance is 95%, so the Playing Handicap is 16.83 × 0.95 = 15.99, rounded to 16. The strokes go on the holes ranked 1 to 16 on the scorecard's handicap (stroke index) row.
What your club and GHIN add
An official index is updated every day you post a score, and the system adds three safeguards that a hand calculation usually skips:
- Soft cap and hard cap: if your index climbs more than 3.0 strokes above your lowest index of the past 12 months, the increase above 3.0 is cut by half, and the total rise is limited to 5.0 (Rule 5.8).
- Exceptional score reduction: a differential at least 7.0 strokes better than your index lowers it by 1.0, or 2.0 if it is 10.0 strokes better (Rule 5.9).
- 9-hole scores: since 2024 a 9-hole score is combined with an expected score for the other nine to make an 18-hole differential.
Frequently asked questions
What does 113 mean in the handicap formula?
113 is the Slope Rating of a course of standard difficulty. Multiplying by 113 ÷ Slope converts your score on any course to what it would be on an average course.
Do I use my gross score or adjusted score?
The adjusted gross score, with each hole capped at net double bogey.
How often is a Handicap Index updated?
Daily. Your index is recalculated the day after you post a score.
For what the result means, see what counts as a good handicap, or go back to the handicap guide.