Section 10 USGA HANDICAP FORMULA

A Handicap Index is the USGA’s service mark used to indicate a measurement of a player’s potential ability on a course of standard difficulty. Potential ability is measured by a player’s best scores, and is expressed as a number taken to one decimal place. These scores are identified by calculating the handicap differential for each score. The USGA Handicap Index is calculated by taking 96 percent of the average of the best handicap differentials, and applying Section 10-3 for golfers with two or more eligible Tournament Scores.

10-1. How to Determine Handicap Differentials

A handicap differential is computed from four elements: adjusted gross score, USGA Course Rating, USGA Slope Rating and 113 (the Slope Rating of a course of standard difficulty). To determine the handicap differential, subtract the USGA Course Rating from the adjusted gross score; multiply the difference by 113; then divide the resulting number by the USGA Slope Rating. Round the final number to the nearest tenth.

Handicap Differential =
(Adjusted Gross Score - USGA Course Rating) x 113 / USGA Slope Rating

a. Plus Handicap Differential

When the adjusted gross score is higher than the USGA Course Rating, the handicap differential is a positive number. Following is an example for determining a differential using an adjusted gross score of 95 made on a course with a USGA Course Rating of 71.5 and a USGA Slope Rating of 125:

Adjusted Gross Score - USGA Course Rating:

 

95 - 71.5 = 23.5

Difference x Standard Slope:

 

23.5 x 113 = 2655.5

Result / USGA Slope Rating:

 

2655.5 / 125 = 21.24

Handicap Differential (rounded):

 

21.2

b. Minus Handicap Differential

When the adjusted gross score is lower than the USGA Course Rating, the handicap differential is a negative number. Following is an example for determining a differential using an adjusted gross score of 69 made on a course with a USGA Course Rating of 71.5 and a USGA Slope Rating of 125:

Adjusted Gross Score - USGA Course Rating:

 

69 - 71.5 = -2.5

Difference x Standard Slope:

 

-2.5 x 113 = -282.5

Result / USGA Slope Rating:

 

-282.5 / 125 = -2.26

Handicap Differential (rounded):

 

-2.3

10-2. USGA Handicap Index Formula

The USGA Handicap Index Formula is based on the best handicap differentials in a player’s scoring record. If a player’s scoring record contains 20 or more scores, the best 10 handicap differentials of the most recent 20 scores are used to calculate the USGA Handicap Index. The percentage of scores used in a scoring record decreases from the maximum of the best 50 percent as the number of scores in the scoring record decreases. If the scoring record contains 9 or 10 scores, only the best three scores (30 to 33 percent) in the scoring record will be used. Thus, the accuracy of a player’s Handicap Index is directly proportional to the number of acceptable scores posted. A USGA Handicap Index shall not be issued to a player who has returned fewer than five acceptable scores. The following procedures illustrate how authorized golf associations and golf clubs calculate a player’s Handicap Index.

The procedure for calculating Handicap Indexes is as follows:

                                i.            Use the table below to determine the number of handicap differentials to use;

Number of
Acceptable Scores

Differentials
To Be Used

5 or 6

Lowest 1

7 or 8

Lowest 2

9 or 10

Lowest 3

11 or 12

Lowest 4

13 or 14

Lowest 5

15 or 16

Lowest 6

17

Lowest 7

18

Lowest 8

19

Lowest 9

20

Lowest 10

                               ii.            Determine handicap differentials;

                              iii.            Average the handicap differentials being used;

                             iv.            Multiply the average by .96; *

                               v.            Delete all numbers after the tenths’ digit. Do not round off to the nearest tenth.

Example 1: Fewer than 20 scores (11 scores available).

Total of lowest 4 handicap differentials:

 

104.1

Average (104.1 / 4):

 

26.025

Multiply average by .96:

 

24.984

Delete digits after tenths:

 

24.9

USGA Handicap Index:

 

24.9

* Bonus for Excellence is the incentive that is built into the USGA Handicap System for players to improve their golf games. It is the term used to describe the small percentage below perfect equity that is used to calculate Handicap Indexes (96%). As his Handicap Index improves (gets lower), the player has a slightly better chance of placing high or winning a handicap event.

Example 2: Twenty Scores available. The following is a sample scoring record of a player with 20 scores.

Total of 10 lowest differentials:

 

154.8

Average (154.8 / 10):

 

15.48

Average multiplied by .96:

 

14.861

Delete all digits after tenths:

 

14.8

USGA Handicap Index:

 

14.8

                             vi.            Apply Section 10-3 for golfers with two or more eligible tournament scores.

Date

USGA
Adjusted
Score

USGA
Course
Rating

Slope
Rating

Handicap
Differential

3/21/97

90

70.1

116

19.4

3/12/97

91

70.1

116

20.4

2/24/97

94

72.3

123

19.9

2/20/97

*88

70.1

116

17.4

1/18/97

89

70.1

116

18.4

1/17/97

*90

72.3

123

16.3

1/16/97

*91

72.3

123

17.2

12/12/96

91

70.1

116

20.4

12/10/96

91

70.1

116

20.4

11/8/96

86

68.7

105

18.6

11/4/96

90

70.1

116

19.4

11/1/96

*92

72.3

123

18.1

10/24/96

*85

68.0

107

18.0

10/16/96

*78

68.7

105

10.0

10/12/96

*82

70.1

116

11.6

10/2/96

*84

70.1

116

13.5

9/14/96

94

72.3

123

19.9

9/5/96

93

72.3

123

19.0

9/4/96

*89

72.3

123

15.3

9/1/96

*88

70.1

116

17.4

* 10 scores with lowest handicap differentials

10-3. Reduction Of USGA Handicap Index Based on Exceptional Tournament Scores

A tournament score is a score made in a competition organized and conducted by a committee in charge of the competition. The competition must identify a winner(s) based on a stipulated round(s), and must be played under the principles of the Rules of Golf.

Using the above definition as a guideline, the committee in charge of the competition shall determine in advance if these conditions are met, and announce in advance whether the score shall be identified by the letter "T" when posted.

Routine events such as regular play days are not normally to be designated as T-Scores because they are not significant in the traditions, schedules, formats and membership of the club.

Examples of inter-club competition scores that should be posted as tournament scores when they meet the above conditions are team matches, competitions restricted by age, member-guest competitions, qualifying rounds for city, state and national competitions, and competitions conducted by golf associations.

Examples of intra-club competition scores that should be posted as tournament scores when they meet the above conditions are low gross-low net competitions, four-ball match or stroke-play competitions, Stableford competitions, and club championships which are stroke or match play, scratch or with handicap.

Eligible Tournament Score — An eligible tournament score is any tournament score made either within the last 12 months or within the player’s current 20-score history.

a. Purpose

The following procedure shall be used as an alternate calculation of a USGA Handicap Index for players with two or more eligible tournament scores. A player’s Handicap Index may be reduced under this procedure when a player has a minimum of two eligible tournament-score differentials that are at least three strokes better than the player’s USGA Handicap Index calculated under Section 10-2.

b. Determination of USGA Handicap Index Based on Tournament Scores

The Handicap Committee shall apply the following steps to determine if there is a reduction in a USGA Handicap Index calculated under Section 10-2.

  1. Calculate the tournament score differentials by subtracting the USGA Course Rating from each eligible tournament score; multiply the result by 113, and divide by the USGA Slope Rating for each course played.
  2. Select the two lowest tournament score differentials. Subtract the second lowest of these differentials from the player’s current Handicap Index. Continue with the next step if the result is 3.0 or greater.

Example: A player with a USGA Handicap Index of 17.6 has three eligible tournament scores in his record. His two scores, which produce the lowest tournament score differentials are 82 and 83. They were made on a course with a USGA Course Rating of 70.6 and a Slope Rating of 130.

Tournament Score -- Course Rating:

 

82-70.6 = 11.4

Difference x 113:

 

11.4 x 113 = 1288.2

Result/Slope Rating:

 

1288.2/130 = 9.9

Lowest Tournament Score Differential:

 

9.9

2nd Lowest Tournament Score Differential:

 

(83-70.6)x113/130=10.8

USGA Handicap Index under Section 10-2:

 

17.6

Second Lowest Differential:

 

-10.8

 

 

6.8

Since 6.8 is greater than 3.0, continue.

 

 
  1. Average the two lowest tournament score differentials.
    (9.9 + 10.8)/2=10.35
  2. Subtract that average from the player’s Handicap Index.
    17.6-10.35=7.25
  3. Using the number derived in step (iv) and the total number of tournament scores in the player’s record, enter the Handicap Reduction Table below to determine the amount the player’s Index is to be reduced.
  4. Subtract the Table value from the player’s Handicap Index. The result of that subtraction will be the player’s USGA Handicap Index provided that it is at least one less than his USGA Handicap Index based on the Formula in Section 10-2.

 

Number of Eligible Tounament Scores

2

3

4

5-9

10-19

20-29

30-39

> 40

Average
of
best
two
T-Score
differentials
below
Handicap
Index

3.0 to 3.4

*

*

*

*

*

*

*

*

3.5 to 3.9

*

*

*

*

*

*

*

*

4.0 to 4.4

1

*

*

*

*

*

*

*

4.5 to 4.9

1.8

1

*

*

*

*

*

*

5.0 to 5.4

2.6

1.9

1

*

*

*

*

*

5.5 to 5.9

3.4

2.7

1.9

1

*