Date Published: 23/01/2026
If you’re tracking your performance under the World Handicap System™ (WHS™), you’ve probably come across the term Score Differential™. But what is Score Differential™ in golf, and how does it affect your handicap?
Understanding this key metric is essential for golfers who want to monitor their improvement or simply keep an accurate handicap index.
In this guide, we’ll break down what Score Differential™ means in golf, how it’s calculated, how it ties into your WHS™ handicap, and what makes a good Score Differential™.
In simple terms, a Score Differential™ is the number that tells you how well you played relative to the difficulty of the course. It adjusts your gross score (before handicap) to account for Course Rating™ and conditions, giving a consistent way to compare rounds played on different courses or from different tees.
It’s the core number used by the WHS™ to calculate your handicap. Rather than using your average score, WHS™ uses the average of your best 8 Score Differentials from your last 20 rounds.
A lower Score Differential™ is better. It means you’ve performed closer to (or better than) par, especially on a tough course.
To understand how Score Differential™ is calculated, you need to know three key numbers:
The formula (used in WHS™) is:
Score Differential™ = (Adjusted Gross Score – Course Rating™) x 113 / Slope Rating
This formula ensures your round is evaluated fairly based on course difficulty.
Score Differential™ is the engine behind the WHS™ handicap system, fairly measuring your performance against the course and forming the basis of your handicap index. Whether you’re playing full rounds or 9-hole formats, submitting scores consistently is the best way to keep your handicap accurate.
With iGolf, you can submit your general play scores at recognised courses and see your WHS™ handicap update in real time. For just £46 a year, it’s a smart, flexible way to track your game – no club membership required.
Yes, 9-hole rounds can also produce a Score Differential™.
A good Score Differential™ depends on your target. Here’s a rough guide:
If you’re regularly producing Score Differentials below your handicap, you can expect your handicap to drop soon.
If you play to your handicap, your expected Score Differential™ will be roughly equal to your handicap index. However, because WHS™ is based on potential, golfers are only expected to “play to their handicap” once every 4–5 rounds. That’s perfectly normal.