Each competitor counts his or her best seven results over the previous two years.  The two year period is calculated on a rolling basis (from today's date to the same date two years previously).  Results less than 1 year old are multiplied by factor 1.5 (Year Weighting Factor) ('YWF').

Taking into account continental distribution, regattas meeting the basic criteria have been awarded a grade by the ISAF Rankings Sub-Committee.  Regattas graded World (W) include the Olympic Regatta, the ISAF World Sailing Championship and the respective Class World Championships.  In principle, Grade 1 events are composed of the top Olympic Classes events and Grade C1 events include the top level continental championships.  Grade 2 events are smaller regional regattas and Grade C2 events include continental championships (other than those included as a Grade C1).  Grade 3 events include small international and national events.  A full set of guidelines on the grading of regattas is available from the ISAF and on the website,

Points for each grade of event are multiplied by a factor to reflect the importance of the event.  This multiplier is called 'F'. The grade of the regatta also determines the percentage of competitors who receive ranking points.  For 'W ' regattas the top 90% of competitors are awarded points; Grade 1 & Grade C1 - 70%; Grade 2 & Grade C2 - 50%; and Grade 3 - 20%.

In addition to its grading, each event is ascribed a Quality factor, 'Q'.  This is calculated according to the number of top competitors attending the regatta.  It can only be calculated when the results have been received.  Q is determined by the formula Q = 1 + n/30, where n is the number of competitors eligible to receive ranking points at the regatta (ie. dependant on the grading of the event) who feature in the top 30 of the most recent ranking list prior to the event.  The limits of Q are set between 1.0 and 1.5. For C1 and C2 events the Q factor is always 1.5.

The winning competitor in each regatta scores 100 points, the second 99 points and so on.  Each competitor's score is multiplied by Q, YWF and F to give the ranking points.  The competitor with the highest total from seven events is listed first in the rankings and so on.

The Olympic Class Rankings are issued approximately eight times a year.

Below explains the method of calculation:

Ranking Points are calculated using the following method.

P = R x F x Q x YWF

Where

P = Ranking Points
R = Regatta Points
F = Event Grading Multiplier
Q = Quality Factor
YWF = Year Weighting Factor

The Regatta Points:

To determine the regatta points (R): 1st = 100 pts, 2nd = 99 pts, 3rd = 98 pts, etc.

The event grading factors are now:

Year Weightings (YWF) are as follows:

Results in the current calendar year (last 12 months) Y=1.5
Results in the past calendar year (last 13 to 24 months)  Y=1.0

Quality Factor:

Quality Factor Q = 1 + N/30
 
 
N is the number of competitors who are eligible for ranking points in the regatta and who are in the top 30 of the last published ranking list.
Q is never less than 1.0 or more than 1.5 For World Championship events and Continental Championships Q is always 1.5 

Add the seven highest values of P over the last two years to determine the competitor's total ranking score.