The Cox-Sprague scoring system is useful for scoring a long series of races where the number of boats varies from race to race. Races with a larger number of competitors get higher weighting.

The Cox-Sprague percentage score for a race series is the total number of points the boat earned in the series divided by the total number of points it could have earned by placing first in every race it started.

The points are awarded using the table below. In each race the number of starters determines the column to be used. Each boat is credited with the number of points indicated for her finishing place. The boats that do not finish (DNF), retire (RET) or are disqualified (DSQ) get points for the place equal to the number of starters plus one. Boats that do not start (DNS) or do not compete (DNC) are not scored.

Since each boat is scored only in the races in which it participates, this gives each boat a chance to compete for the series awards without the need to enter every race. A boat needs to start a minimum number of races, typically 40% to 60% of all races in the series, to be eligible for series prizes.

For example, if a boat places 2nd among 5 boats in one race and 3rd among 4 in another, the boat earns 46 out of a possible 52 in the first race and 33 out of a possible 43 in the second. Its percentage for the two races it sailed is (46+33)/(52+43) = 79/95 = 83.16%.

A boat that wins every race it enters earns a series percentage score of 100%. A boat that finishes last in a race receives percentage scores ranging from 59% (=59/100) in a 20 boat race to 67.7% (=21/31) in a three boat race. The original Cox-Sprague table awarded 40% to a boat finishing second in a two boat race. The table below has been modified to award 70% for the second place finish in a two boat race and 50% for DNF or DSQ in a two boat race for consistency with the rest of the table.

Cox-Sprague Table

Place                 Number of Starters
         2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20

 1      10 31 43 52 60 66 72 76 80 84 87 90 92 94 96 97 98 99 100
 2       7 25 37 46 54 60 66 70 74 78 81 84 86 88 90 91 92 93 94
 3       5 21 33 42 50 56 62 66 70 74 77 80 82 84 86 87 88 89 90
 4       . 17 29 38 46 52 58 62 66 70 73 76 78 80 82 83 84 85 86
 5       .  . 26 35 43 49 55 59 63 67 70 73 75 77 79 80 81 82 83
 6       .  .  . 32 40 46 52 56 60 64 67 70 72 74 76 77 78 79 80
 7       .  .  .  . 38 44 50 54 58 62 65 68 70 72 74 75 76 77 78
 8       .  .  .  .  . 42 48 52 56 60 63 66 68 70 72 73 74 75 76
 9       .  .  .  .  .  . 46 50 54 58 61 64 66 68 70 71 72 73 74
10       .  .  .  .  .  .  . 48 52 56 59 62 64 66 68 69 70 71 72
11       .  .  .  .  .  .  .  . 50 54 57 60 62 64 66 67 68 69 70
12       .  .  .  .  .  .  .  .  . 52 55 58 60 62 64 65 66 67 68
13       .  .  .  .  .  .  .  .  .  . 53 56 58 60 62 63 64 65 66
14       .  .  .  .  .  .  .  .  .  .  . 55 57 59 61 62 63 64 65
15       .  .  .  .  .  .  .  .  .  .  .  . 56 58 60 61 62 63 64
16       .  .  .  .  .  .  .  .  .  .  .  .  . 57 59 60 61 62 63
17       .  .  .  .  .  .  .  .  .  .  .  .  .  . 58 59 60 61 62
18       .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 58 59 60 61
19       .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 58 59 60
20       .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 58 59
21       .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 58

Cox-Sprague Calculator