HandicapCalc
The basics of how handicaps are calculated

Overview of handicap calculation

What is a handicap?  A handicap is a way to compare golfer's abilities, and allow for equitable competition among golfers of different abiltiies.

A handicap is not, as many believe, supposed to represent your average score.  It shows your scoring ability, or what you can expect to shoot on a course when playing well.    Your handicap is based on the better half of your last twenty scores, and takes 96% of that average..  So, it is weighted towards the better end of your recent performance history.

DivotTracker cannot give you an "official" USGA handicap index.  You need to use a sanctioned organization to provide that.   DivotTracker is only intended to give you a way to track your scores outside of that organization, or instead of an official handicap.   By using the USGA handicapping rules, the handicap that DivotTracker calculates should be equal to that calculated by an official handicapping body.

More precise and official information can be found at the USGA's www site:  http://www.usga.org/playing/handicaps/manual/handicap_system_manual.html

Steps in Calculating Handicap

0) Adjustments -- See notes at bottom of page.

1)  For each round, a handicap differential is calculated.   This is your score on that round, minus the course rating, and adjusted for the course's slope rating.   So, I play a course with a rating of 70.9, and a slope of 126 and my score is a 79.  The handicap differential for that round would be:

( 79 - 70.9 )  *  113/126 = 7.26428571

The resulting number is then rounded to the nearest tenth.  The handicap differential for this round is 7.3
This number is shown in the DivotTracker table of rounds as the 'diff' (or Index, depending on version).  This number provides a good measure of performance, as an 85 on a very easy course is much different than an 85 on a very hard course.

2) Of the last twenty rounds played, I take the ten lowest handicap differentials, and discard the other ten.
I then average those ten scores -- add them all together and divide by ten.  For example, my 10 best rounds might be from 6.3 to 12.1, and average out to 8.955

3)  Take 96% of your differentials average.  (Multiply the average of the differentials by
0.96).    8.955 * 0.96 = 8.5968

4)  Truncate the adjusted average at  the tenths digit (do not round it up/down, simply delete any numbers after the tenths digit).  So, the resulting player handicap is:  8.5