Score differentials, Handicap Index and Course Handicap under the WHS
Updated October 2026
Score differentials are listed in your scoring record in the GHIN app or your association’s handicap service; paste up to 20, most recent first. To convert one round yourself, enter the adjusted gross score and the course rating and slope of the tees you played, printed on the scorecard. Today’s slope, course rating and par turn the Index into strokes for the round.
Differential = (adjusted gross score − course rating − any playing-conditions adjustment) × 113 ÷ slope. For a 95 on tees rated 71.5 with slope 125: (95 − 71.5) × 113 ÷ 125 = 21.24, recorded as 21.2. From the 20 default differentials, the lowest eight are 9.8, 10.2, 10.9, 11.0, 11.5, 11.8, 12.2 and 12.4; they total 89.8, and 89.8 ÷ 8 = 11.225, a Handicap Index of 11.2. Course Handicap = 11.2 × 130 ÷ 113 + (71.8 − 72) = 12.685, which rounds to 13 strokes.
| 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 |
| 7–8 | Average of lowest 2 | 0 |
| 9–11 | Average of lowest 3 | 0 |
| 12–14 | Average of lowest 4 | 0 |
| 15–16 | Average of lowest 5 | 0 |
| 17–18 | Average of lowest 6 | 0 |
| 19 | Average of lowest 7 | 0 |
| 20 | Average of lowest 8 | 0 |
The same golfer’s Index at different points in the record, using the default differentials:
| Differentials in record | Rule | Handicap Index |
|---|---|---|
| 3 most recent | Lowest 1, -2.0 | 7.8 |
| 6 most recent | Lowest 2, -1.0 | 9.4 |
| 10 most recent | Lowest 3 | 10.3 |
| 20 most recent | Lowest 8 | 11.2 |
| Tees (11.2 Index) | Unrounded | Course Handicap |
|---|---|---|
| Forward tees: rating 68.0, slope 113, par 72 | 7.20 | 7 |
| Middle tees: rating 70.2, slope 124, par 72 | 10.49 | 10 |
| Default: rating 71.8, slope 130, par 72 | 12.68 | 13 |
| Back tees: rating 74.6, slope 140, par 72 | 16.48 | 16 |
Harder tees give more strokes: slope scales the Index, and the course rating minus par adds or removes strokes for tees that play above or below par. Competitions may then apply a handicap allowance to get a playing handicap.
A Handicap Index is issued once you post scores totaling 54 holes, from any mix of 9- and 18-hole rounds, and it is updated daily after a score is posted. The maximum Index is 54.0. Each hole is capped at net double bogey (double bogey plus any handicap strokes you receive on the hole) before the differential is computed. A score 7.0 to 9.9 strokes better than your Index cuts it by 1.0, and 10.0 or more by 2.0 (exceptional score reduction). If your Index rises more than 3.0 strokes above your lowest Index of the past 12 months, further increases are cut by half (soft cap), and it cannot rise more than 5.0 strokes (hard cap).
Using gross scores instead of differentials. A 90 on a hard course and a 90 on an easy one are different performances; only differentials are comparable.
Applying the old 0.96 multiplier. The pre-2020 USGA formula multiplied by 0.96. The WHS averages the best 8 of 20 with no multiplier.
Forgetting net double bogey. A 10 on a par 4 should be posted as the capped score, which lowers the differential.
Expecting caps and reductions here. The calculator averages the differentials you enter; it does not apply caps, exceptional score reductions or playing-conditions adjustments, so the official Index from your association can differ.