"Handicap Index" and "Course Handicap" get used interchangeably at the golf course, but they measure two different things — one describes you, the other describes you on a specific course. Mixing them up is the most common handicap confusion under the World Handicap System (WHS).
The short version
- Handicap Index — a portable number that describes your general playing ability, independent of any course. It travels with you everywhere you play.
- Course Handicap — your Handicap Index converted for one specific set of tees at one specific course, adjusted for how much harder or easier that course plays.
Your Handicap Index doesn't change when you switch courses. Your Course Handicap does — because it accounts for that course's difficulty.
How they connect
Course Handicap is derived from Handicap Index using the course's Slope Rating, plus a small adjustment for how the course's par compares to its Course Rating:
Course Handicap = Handicap Index × (Slope Rating ÷ 113) + (Course Rating − Par)
Result is rounded to the nearest whole number.
113 is the Slope Rating of a course of "standard" difficulty under WHS — so if you play a
harder-than-average course (Slope Rating above 113), your Course Handicap will be higher
than your Handicap Index; on an easier course, it'll be lower. The (Course Rating − Par) term
folds in the fact that a course's rated difficulty for a scratch golfer doesn't always land
exactly on par.
Example: a 12.4 Handicap Index at a course with a Slope Rating of 130, Course Rating 72.3, and Par 72: Course Handicap = 12.4 × (130 ÷ 113) + (72.3 − 72) ≈ 14.6, which rounds to 15 strokes for that round.
How Handicap Index itself is built
Handicap Index isn't a single round's score — it's built from your Score Differentials (one per round played), which already adjust for that round's course rating and slope. WHS then averages your best few differentials out of your most recent 20 rounds, with the exact count phased in as you build scoring history (as few as 1 score needed to start, scaling to your best 8 of 20 once you have full history), applies a small downward adjustment for smaller samples, and multiplies by 0.96 before truncating to one decimal.
That 96% factor is deliberate — WHS is built around your demonstrated potential, not a straight average of every round you've ever shot, so your Handicap Index tends to run a bit lower than your typical score would suggest.
Why this order of operations matters
Because Handicap Index is portable and Course Handicap is course-specific, you calculate them in a fixed order: play rounds → derive a Score Differential per round → combine differentials into a Handicap Index → convert that Handicap Index into a Course Handicap for wherever you're playing next. Skipping straight from raw scores to a "handicap" without going through Score Differential and the official lowest-N table will produce a number that doesn't match what WHS actually specifies.