How do I calculate a score differential in golf?
A Score Differential converts one round into a number you can compare across any course. Enter your adjusted gross score, course rating, and slope rating to get it, with the formula and a worked example below.
The formula
Score Differential = (113 ÷ Slope Rating) × (Adjusted Gross Score − Course Rating − PCC)
- 113 is the slope rating of a course of standard relative difficulty — the constant every course is measured against.
- PCC is the Playing Conditions Calculation, an adjustment between −1 and +3 applied on days when the field scored abnormally. It is 0 most of the time.
- The result is rounded to one decimal place.
What the formula is actually doing
Subtracting the course rating answers "how did I do against what a scratch golfer is expected to shoot here?" Shoot 85 on a course rated 71.0 and you were 14 strokes worse than the scratch expectation.
Multiplying by 113 ÷ slope answers "how hard was this course for someone who is not scratch?" Slope measures exactly that. On a brutal course with a slope of 140, those 14 strokes count for less; on a gentle 113-slope course, they count in full.
The output is portable. A 13.0 differential from a resort course and a 13.0 from your home track represent the same quality of golf.
A worked example
Adjusted gross score 85, course rating 71.0, slope rating 122, PCC 0.
85 − 71.0 = 14.0. Then 113 ÷ 122 = 0.926. And 14.0 × 0.926 = 12.97, which rounds to a Score Differential of 13.0.
Play the same 85 from tees rated 74.5 with a slope of 140 and the differential drops to 8.5 — the harder tees make the identical score a better round.
The same score across different slopes
Every row below assumes a course rating of 71.0 and a PCC of 0, so you can see slope alone at work.
| Adjusted gross | Slope 113 | Slope 122 | Slope 131 | Slope 140 |
|---|---|---|---|---|
| 80 | 9.0 | 8.3 | 7.8 | 7.3 |
| 85 | 14.0 | 13.0 | 12.1 | 11.3 |
| 90 | 19.0 | 17.6 | 16.4 | 15.3 |
| 95 | 24.0 | 22.2 | 20.7 | 19.4 |
| 100 | 29.0 | 26.9 | 25.0 | 23.4 |
Adjusted gross, not raw gross
The score that goes into the formula is capped hole by hole at net double bogey: par + 2 + the handicap strokes you receive on that hole. One disaster hole cannot distort your handicap record.
A 10 on a par 3 where you get no strokes is posted as a 5. Everything else on the card stands as played.
Common questions
- What does 113 mean in the handicap formula?
- 113 is the slope rating of a course of standard playing difficulty. Dividing 113 by the actual slope scales your score relative to that standard, which is what makes differentials comparable between courses.
- What is PCC in golf?
- The Playing Conditions Calculation. When scoring across a course on a given day is abnormally high or low, an adjustment between −1 and +3 is applied to every differential from that day. It is 0 on most days.
- Can a score differential be negative?
- Yes. Shoot better than the course rating and the differential is negative, which is exactly how plus handicaps are built.
- How many differentials do I need?
- Three to produce an index at all, and 20 before the standard "lowest 8 of the last 20" rule applies.
Track this automatically
BirdieCap is BirdieConnect's free, automatic, WHS-style handicap index. It builds from the rounds you play, supports 9-hole and 18-hole scores, and is unofficial — it is not issued or endorsed by the USGA, The R&A, or GHIN. See how BirdieCap works.