How is my Handicap Index calculated?

Q: How is my Handicap Index calculated?

Once you have 20 scores, your Handicap Index is the average of your best 8 Score Differentials out of your most recent 20, rounded to the nearest tenth (Rule 5.2b of the Rules of Handicapping). With fewer than 20 scores (Rule 5.2a), fewer differentials are used, with an adjustment in the early stages: Scores in your 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 or 8 Average of lowest 2 0 9 Average of lowest 3 0 The number used keeps rising as your record grows, until it's the best 8 of 20. Expect your Handicap Index to move around a lot in the early stages. Then the safeguards are applied: Caps: if the result is more than 3.0 above your Low Handicap Index (your lowest in the past 365 days), the soft cap slows the rise by 50%; it can never go more than 5.0 above it (hard cap). Exceptional scores: a differential 7.0 or more better than your Handicap Index gives an extra reduction of 1.0 or 2.0. When it changes: your Handicap Index is updated overnight, the day after you submit a score. What to expect: because it's based on your best rounds, most players score about 2 to 5 strokes above their handicap in most rounds and play to it about 20% of the time. The maximum Handicap Index is 54.0.

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Accepted Answer

Once you have 20 scores, your Handicap Index is the average of your best 8 Score Differentials out of your most recent 20, rounded to the nearest tenth (Rule 5.2b of the Rules of Handicapping).

With fewer than 20 scores (Rule 5.2a), fewer differentials are used, with an adjustment in the early stages:

Scores in your 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 or 8	Average of lowest 2	0
9	Average of lowest 3	0

The number used keeps rising as your record grows, until it's the best 8 of 20. Expect your Handicap Index to move around a lot in the early stages.

Then the safeguards are applied:

Caps: if the result is more than 3.0 above your Low Handicap Index (your lowest in the past 365 days), the soft cap slows the rise by 50%; it can never go more than 5.0 above it (hard cap).
Exceptional scores: a differential 7.0 or more better than your Handicap Index gives an extra reduction of 1.0 or 2.0.