The Complete Guide to the World Handicap System
By Arshi Khan, Founder of Just4Marketing · Last reviewed October 2026
Since 2020, golfers in most countries have used the World Handicap System (WHS), which gives every player a Handicap Index that travels with them to any rated course. Your index is based on your best recent rounds, adjusted for how difficult each course was. This guide explains score differentials, how many rounds count, and how to turn an index into strokes on the course you're playing.
Score differentials and course difficulty
A score of 90 means different things on an easy course and a hard one. The course rating is the expected score of a scratch golfer, and the slope rating (from 55 to 155, with 113 as average) measures how much harder the course plays for a bogey golfer. The differential converts each round into a common scale, so rounds from different courses can be averaged fairly.
The playing conditions calculation (PCC) adjusts for unusually hard or easy days, such as high winds. It's set by the handicapping authority after the day's scores are in; for casual calculations it's usually 0.
How many differentials count
| Rounds on record | Differentials used | Adjustment |
|---|---|---|
| 3 | Lowest 1 | −2.0 |
| 4 | Lowest 1 | −1.0 |
| 5 | Lowest 1 | 0 |
| 6 | Average of lowest 2 | −1.0 |
| 7–8 | Average of lowest 2 | 0 |
| 9–11 | Average of lowest 3 | 0 |
| 12–14 | Average of lowest 4 | 0 |
| 15–16 | Average of lowest 5 | 0 |
| 17–18 | Average of lowest 6 | 0 |
| 19 | Average of lowest 7 | 0 |
| 20 | Average of lowest 8 | 0 |
Keeping your handicap accurate
Post every acceptable round
Leaving out bad rounds makes your index lower than your true ability and causes problems in competitions.
Use the right tees' ratings
Course and slope ratings differ by tee. Use the ratings for the tees you actually played.
Treat this as an estimate
Official indexes also apply caps on how fast an index can rise. Your national golf body's figure is the one that counts.
Frequently asked questions
How is a Handicap Index calculated?
Each round produces a score differential: (113 ÷ slope rating) × (adjusted gross score − course rating − playing conditions calculation). With 20 rounds, your Handicap Index is the average of your best 8 differentials.
How many rounds do I need?
You can get an index after 54 holes — for example three 18-hole rounds. With fewer than 20 rounds, the system uses fewer differentials and, for 3, 4, and 6 rounds, applies a small reduction.
What is an adjusted gross score?
It's your score after limiting each hole to a maximum, which under WHS is net double bogey: par plus 2 plus any handicap strokes you receive on that hole. It stops one disastrous hole from distorting your handicap.
What's the difference between Handicap Index and course handicap?
Your Handicap Index is the same everywhere. Your course handicap is the number of strokes you receive on a specific course and set of tees: index × (slope ÷ 113) + (course rating − par).