How is a score differential calculated?

Score Differential = (113 / Slope Rating) × (Adjusted Gross Score − Course Rating). The constant 113 is the slope of a course of standard difficulty.

How many differentials count toward my index?

Under the World Handicap System the number depends on how many scores you have. With a full set of 20 rounds, your Handicap Index is the average of your best 8 differentials; fewer rounds use a smaller table.

Is any of my scoring data uploaded?

No — every calculation runs locally in your browser and nothing is sent anywhere.

Golf Handicap Calculator

Score differentials and Handicap Index using the World Handicap System.

Golf handicap calculator

Two tools in one, built on the World Handicap System (WHS). First, turn a single round into a score differential from your adjusted gross score, the course rating and the slope rating. Then enter your recent differentials to get your Handicap Index.

The differential formula is (113 / Slope) × (Score − Rating), and your index is the average of your lowest qualifying differentials. Everything runs in your browser — your scores never leave your device.