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100 handicap cells — the same 90 means different things on different courses

The World Handicap System writes a course’s difficulty as two numbers: the Course Rating is what a scratch golfer is expected to shoot, and the Slope Rating says how much harder an average player finds it. Every meeting of 10 scores and 10 slope ratings gets its score differential worked out.

90 · Score Differential

  • Slope Rating 5537 · ×2.055
  • Slope Rating 7527.1 · ×1.507
  • Slope Rating 9521.4 · ×1.189
  • Slope Rating 10519.4 · ×1.076
  • Slope Rating 11318 · ×1
  • Slope Rating 12017 · ×0.942
  • Slope Rating 13015.6 · ×0.869
  • Slope Rating 14014.5 · ×0.807
  • Slope Rating 14813.7 · ×0.764
  • Slope Rating 15513.1 · ×0.729

The formula is one multiplication

Differential = (adjusted gross score − Course Rating) × 113 ÷ Slope Rating. 113 is the slope of a course of standard difficulty, so on such a course the multiplier is exactly one and changes nothing. This table assumes a par-72 course rated 72.0, which isolates what the slope alone does.

A harder course makes the same score better

A bigger slope divides 113 by more, so the differential comes out smaller. Ninety strokes on a slope-155 course is a far better round than ninety on a slope-95 course. The rules allow slopes from 55 to 155, and most courses land between 105 and 145.

One round is not an index

A Handicap Index is the average of the best eight differentials from your last twenty rounds. What this table gives is therefore not an index but **the differential a single round produces**. That averaging is also why one good day barely moves an index: only eight of twenty scores count, and the other twelve do nothing.

The Course Handicap puts it back

If the differential strips a course’s difficulty out, the Course Handicap puts it back in: index × slope ÷ 113 + (Course Rating − par). Where the rating equals par, as here, the two steps cancel and you land on the original strokes. It also means that the tougher today’s course, the more strokes you receive.

What this table assumes

It assumes a par-72 course rated exactly 72.0. Real courses rate above or below par, and that gap enters the arithmetic directly. The adjusted gross score is also capped hole by hole at net double bogey, so it can differ from what you actually wrote down, and a playing-conditions adjustment may be applied for the day.

Find it by score and slope

Score Differential

Slope Rating 55Slope factor ×2.055

72 · 55
0
75 · 55
6.2
78 · 55
12.3
81 · 55
18.5
85 · 55
26.7
90 · 55
37
95 · 55
47.3
100 · 55
57.5
108 · 55
74
115 · 55
88.3

Slope Rating 75Slope factor ×1.507

72 · 75
0
75 · 75
4.5
78 · 75
9
81 · 75
13.6
85 · 75
19.6
90 · 75
27.1
95 · 75
34.7
100 · 75
42.2
108 · 75
54.2
115 · 75
64.8

Slope Rating 95Slope factor ×1.189

72 · 95
0
75 · 95
3.6
78 · 95
7.1
81 · 95
10.7
85 · 95
15.5
90 · 95
21.4
95 · 95
27.4
100 · 95
33.3
108 · 95
42.8
115 · 95
51.1

Slope Rating 105Slope factor ×1.076

72 · 105
0
75 · 105
3.2
78 · 105
6.5
81 · 105
9.7
85 · 105
14
90 · 105
19.4
95 · 105
24.8
100 · 105
30.1
108 · 105
38.7
115 · 105
46.3

Slope Rating 113Slope factor ×1

72 · 113
0
75 · 113
3
78 · 113
6
81 · 113
9
85 · 113
13
90 · 113
18
95 · 113
23
100 · 113
28
108 · 113
36
115 · 113
43

Slope Rating 120Slope factor ×0.942

72 · 120
0
75 · 120
2.8
78 · 120
5.7
81 · 120
8.5
85 · 120
12.2
90 · 120
17
95 · 120
21.7
100 · 120
26.4
108 · 120
33.9
115 · 120
40.5

Slope Rating 130Slope factor ×0.869

72 · 130
0
75 · 130
2.6
78 · 130
5.2
81 · 130
7.8
85 · 130
11.3
90 · 130
15.6
95 · 130
20
100 · 130
24.3
108 · 130
31.3
115 · 130
37.4

Slope Rating 140Slope factor ×0.807

72 · 140
0
75 · 140
2.4
78 · 140
4.8
81 · 140
7.3
85 · 140
10.5
90 · 140
14.5
95 · 140
18.6
100 · 140
22.6
108 · 140
29.1
115 · 140
34.7

Slope Rating 148Slope factor ×0.764

72 · 148
0
75 · 148
2.3
78 · 148
4.6
81 · 148
6.9
85 · 148
9.9
90 · 148
13.7
95 · 148
17.6
100 · 148
21.4
108 · 148
27.5
115 · 148
32.8

Slope Rating 155Slope factor ×0.729

72 · 155
0
75 · 155
2.2
78 · 155
4.4
81 · 155
6.6
85 · 155
9.5
90 · 155
13.1
95 · 155
16.8
100 · 155
20.4
108 · 155
26.2
115 · 155
31.3

How to read this

  • Differential = (gross score − Course Rating) × 113 ÷ Slope.
  • 113 is standard difficulty, so at slope 113 nothing changes.
  • The higher the slope — the harder the course — the better the same score reads.
  • A Handicap Index averages the best eight of your last twenty rounds.

Frequently asked questions

Q. What is a Slope Rating?

A number for how much harder an average player finds the course than a scratch golfer does. It runs from 55 to 155, with 113 as standard.

Q. Why 113 of all numbers?

It is defined as the slope of a course of standard difficulty, so at slope 113 the factor is exactly one and changes nothing.

Q. Is 90 on a hard course really better?

Yes. Ninety on a slope-155 course produces a much lower differential than ninety on a slope-95 course.

Q. Does one round set a handicap?

No. The index averages the best eight differentials from your last twenty rounds.

Q. How does the Course Handicap differ?

It puts the index back onto today’s course: index × slope ÷ 113 + (Course Rating − par).