Golf Score Differential Calculator
Compute the World Handicap System score differential from an adjusted gross score, course rating and slope — the building block of your handicap index.
How it works
Score differential = (113 ÷ slope rating) × (adjusted gross score − course rating − PCC)
The score differential is how the World Handicap System converts one round into a comparable number regardless of which course you played. It measures your strokes above the course rating, then scales them to a standard slope of 113 so that a hard course and an easy one contribute fairly. Your handicap index is the average of your best 8 differentials out of your most recent 20, which is why a single low differential can move your index quickly.
Worked example
With an adjusted gross of 92, a course rating of 72.4, a slope of 128 and no PCC adjustment: (113 ÷ 128) × (92 − 72.4 − 0) = 0.883 × 19.6 = 17.3.
Sources: USGA — World Handicap System
Frequently asked questions
What is slope rating?
Slope measures how much harder a course plays for a bogey golfer than for a scratch golfer, on a scale of 55 to 155. The average course is 113, which is why 113 appears in the formula as the normalising constant.
What is the PCC?
The Playing Conditions Calculation is a daily statistical adjustment (from −1 to +3 strokes) the handicap system applies when scores across the field show the course played unusually hard or easy. Most days it is zero.
How does this become my handicap index?
Each round produces one differential. Your index is the average of the lowest 8 differentials among your most recent 20 scores, so lower differentials are what pull your handicap down.
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This calculator is for educational purposes. Double-check important results before acting on them.