Enter up to 20 recent 18-hole rounds: your adjusted gross score plus the course rating and slope of the tees you played. The calculator works out each score differential and your estimated Handicap Index using the World Handicap System (WHS) formula.
| # | Score | Course rating | Slope | Differential |
|---|
Score differential = (113 / slope) x (adjusted gross score - course rating - PCC). PCC is the playing conditions calculation, usually 0. Handicap Index = average of the lowest 8 of your last 20 differentials, rounded to one decimal, capped at 54.0. Course handicap = Handicap Index x (slope / 113) + (course rating - par), rounded to a whole number.
Example (pre-filled above): five rounds give differentials 18.4, 15.9, 19.8, 16.6, 15.3. With 5 rounds the lowest one is used, so the Handicap Index is 15.3.
| Rounds | Lowest differentials used | Adjustment |
|---|---|---|
| 3 | 1 | -2.0 |
| 4 | 1 | -1.0 |
| 5 | 1 | 0 |
| 6 | 2 | -1.0 |
| 7 | 2 | 0 |
| 8 | 2 | 0 |
| 9 | 3 | 0 |
| 10 | 3 | 0 |
| 11 | 3 | 0 |
| 12 | 4 | 0 |
| 13 | 4 | 0 |
| 14 | 4 | 0 |
| 15 | 5 | 0 |
| 16 | 5 | 0 |
| 17 | 6 | 0 |
| 18 | 6 | 0 |
| 19 | 7 | 0 |
| 20 | 8 | 0 |
Under the World Handicap System, each round gives a score differential: (113 / slope rating) x (adjusted gross score - course rating - PCC). Your Handicap Index is the average of the lowest 8 of your most recent 20 differentials, rounded to one decimal.
You can get a Handicap Index after 3 rounds (54 holes). With fewer than 20 rounds a smaller number of lowest differentials is used, with a small adjustment for 3, 4 and 6 rounds, as shown in the table on this page.
The Handicap Index measures your ability on a course of standard difficulty. The course handicap is the number of strokes you get on a specific course and tees: Index x (slope / 113) + (course rating - par).
Slope shows how much harder a course plays for a bogey golfer than for a scratch golfer. It ranges from 55 to 155; 113 is average. Course rating and slope are printed on the scorecard or listed by your golf association.
No. This calculator uses the published WHS formulas for an estimate. It skips the soft and hard caps, exceptional score reductions and net double bogey adjustments that your club or national association applies to an official index.
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