Golf Handicap Index Calculator

Work out your handicap index from one round's adjusted score, course rating and slope.

Result

16.6

How it is calculated

The tool computes the World Handicap System score differential for one round: differential = (adjusted gross score − course rating) × 113 ÷ slope rating. The adjusted gross score is your total strokes after capping each hole at the maximum allowed. Course rating and slope rating are printed for each set of tees on the scorecard, and 113 is the slope of a course of standard difficulty. The slope must be between 55 and 155; outside that range, or with a zero or negative score or rating, there is no result. The answer is rounded to one decimal and is negative when you beat the course rating. It applies no weather adjustment, and it shows one round's differential, not your official index, which averages the best differentials of your recent rounds.

Worked example

You shoot an adjusted gross score of 90 on tees with a course rating of 71.2 and a slope rating of 128. Score above rating = 90 − 71.2 = 18.8. Scaling factor = 113 ÷ 128 = 0.8828. Differential = 18.8 × 0.8828 = 16.6. On the same tees with a slope of 140 the same 90 gives 15.2, and with a slope of 113 it gives 18.8, because a harder course (higher slope) shrinks the differential.

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Common mistakes

  • Typing the raw score when a hole went badly wrong. The tool expects the adjusted gross score with the hole cap applied, and an unadjusted number gives a differential that is too high.
  • Confusing course rating with par. The rating is a decimal such as 71.2 and usually differs from par (70, 71, 72).
  • Using the rating and slope of the wrong tees. Each set of tees has its own pair, so use the one for the tees you played.
  • Swapping the rating and slope fields. A rating of 128 is outside the 40–90 range the tool accepts for course ratings, so it shows no result; check that the rating (near par) and the slope (55–155) are in the right fields.
  • Reading one differential as your handicap index. The official index comes from the best differentials of your recent rounds, so a single round will not match it.

About this calculator

The World Handicap System (WHS) converts a round's adjusted gross score into a score differential using the formula (adjusted gross score − course rating) × 113 ÷ slope rating, which normalizes the raw score for how hard that specific course played that day — course rating reflects the expected score of a scratch golfer, and slope rating (ranging 55-155, with 113 as standard difficulty) reflects how much harder the course plays for a bogey golfer relative to a scratch golfer. A golfer's handicap index is then derived by averaging the best differentials from their most recent rounds.

Golfers use their handicap index to get course handicaps at any course they play — even one they've never seen before — because the index travels with the golfer while the conversion to a specific course happens locally using that course's own rating and slope, which is what makes it possible for golfers of very different skill levels to compete fairly against each other.

This calculator takes your adjusted gross score, the course rating and the slope rating for a single round, and returns that round's score differential, rounded to one decimal. The figure shown under the handicap index label is this single-round differential only: it is not averaged over your best rounds, so it is the building block of your official handicap index rather than the index itself.

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