Handicap Index calculator.

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.

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.

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.

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.

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.

The index travels; the strokes do not. Course Handicap = Index × (Slope ÷ 113) + (Course Rating − Par), rounded to the nearest whole stroke. That is why an 18.0 index plays off a different number at a 145-slope championship layout than at a gentle 108-slope course — the index is the input to that sum, never the strokes themselves.

Yes, and that is the whole point of the World Handicap System. Until 2020 those countries each ran their own scheme — CONGU in Britain and Ireland, the USGA system in America, and four others besides — and an index did not travel between them. WHS merged all six into one calculation, so the figure this produces reads the same in England, Ireland, South Africa, Canada or the United States. Your national body still holds your record; the arithmetic is shared.

Course rating and slope exist precisely because a score is meaningless without the course. The same principle runs through the archive back to 1860: the number is only readable next to the conditions that produced it.

An index measures consistency against a course, not what a player did with a tournament live in front of them. Player-of-the-Year honours and the scoring award answer that second question, and golf keeps them separate for exactly that reason.

Nine-hole rounds count. Under the World Handicap System a nine-hole round produces its own differential and two of them combine into an eighteen-hole equivalent, so half-rounds are not wasted — which also means the same index method now travels across countries that once each ran their own.