It is important to note that your Index is based on your peak performance, not your average performance. Thus, a golfer whose average score is 12 strokes over the Course Rating will have a Handicap Index in the neighborhood of 9.0.
Your Handicap Index takes your 20 most recent scores, factors in Course Rating and Slope Rating, and arrives at a number that includes a decimal point and is calculated out to the tenths place. As such, your Index might be 4.6, or 12.4, or 21.8, etc. Your Index is adjusted on a regular basis, usually once every two weeks when golf is “in season” in your part of the country. (In other words, if you live in Florida, you receive a new Index every two weeks year-round. If you live in New York, you receive a new Index every two weeks from April 1 to October 31.)