How is a Handicap Index calculated?
Each round becomes a score differential — 113 divided by the slope rating, times your adjusted score minus the course rating. Your index is the average of your best differentials: the best 8 of a full 20-round record.
What if I have fewer than 20 rounds?
The World Handicap System uses a sliding table: at 3 rounds it takes your single best differential minus two strokes, by 9 rounds your best 3, and from 20 rounds onward the best 8.
What do slope and course rating mean?
Course rating is what a scratch golfer would shoot; slope (55–155, with 113 as standard) measures how much harder the course plays for a bogey golfer. Together they let a score travel between courses fairly.
What is a good Handicap Index?
The system caps at 54.0. A typical committed club golfer sits near 15–20, single digits is genuinely strong, and a plus index — better than scratch — means you give strokes back to the course.
Why is my index lower than my average score suggests?
Because it deliberately uses only your BEST rounds, not all of them. The index measures your demonstrated potential, which is why most golfers play a few strokes above it on an ordinary day.