Your Handicap Index is calculated the day after you have posted scores from 54-holes to your scoring record made up of any combination of 9- or 18-hole rounds.
It is calculated the same way around the world, using Course Rating™ and Slope Rating™: your best 8 Score Differentials™ from your most recent 20 scores are averaged for your Handicap Index.
All playing abilities are welcome. A Handicap Index delivers benefits for golfers of all skill levels.