How is a golf handicap calculated?
Under the World Handicap System, a golfer's handicap index is calculated from their best recent scores, each adjusted for the difficulty of the course and tees played, and updated after every round submitted.
The World Handicap System replaced the old country-specific systems with one shared calculation, and came into effect across Great Britain and Ireland on 2 November 2020, developed by The R&A and the USGA. Every qualifying round becomes a Score Differential, and Rule 2 of the Rules of Handicapping requires that round to have been played on a course carrying a current Course Rating and Slope Rating, so the difficulty of the course you played is built into the number rather than ignored.
The sum itself
Rule 5.2b sets it: average the lowest eight of your most recent twenty Score Differentials and round to the nearest tenth, which is why a single terrible round barely moves it while a genuine run of form does. Rule 5.4 says it should be updated no later than the day after a score is submitted, so it moves with your golf rather than once a season.
The index is not the number you play off
The Handicap Index is converted: it is converted for the course and tee you are on into a Course Handicap, and then into a Playing Handicap that applies the competition's handicap allowance (Rules of Handicapping, Rule 6), which is the figure that appears on the card. To try it on your own record, the handicap calculator performs exactly this Rule 5.2b arithmetic on the differentials your club's app shows. Which is exactly why what counts as a good handicap only makes sense once you know how the number's built. Whatever it reads today, our golf gifts mark the round that mattered.
This sits in the game with twelve other answers. From here, Stableford scoring shows the handicap actually being used on a card, and par is the baseline the whole calculation hangs off.
Written by Craig Fearn, The Golf Gift Co. Last updated .