Golf Handicap Calculator
A fair game, by the numbers.
Golf Handicap Calculator
Turn a score into a differential, then build a Handicap Index from your recent rounds.
Differential for that round13
Recent differentials (7/20)
- Round 112.4
- Round 214.1
- Round 310.8
- Round 413.6
- Round 511.9
- Round 615.2
- Round 79.7
A Handicap Index needs at least three 18-hole differentials and uses the best rounds from the most recent 20. The WHS table applies a small adjustment when only three to six rounds are available.
10.3
Based on the best 2 of 7 differentials
- Differentials entered
- 7
- Rounds counted
- 2
- WHS adjustment
- None
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What This Calculator Does
The Golf Handicap Calculator converts a score into a score differential using the course rating and slope, then builds a Handicap Index from your recent differentials. It applies the World Handicap System rule that counts only your best rounds from the most recent 20.
How It Works
A differential is (adjusted gross score − course rating) × 113 ÷ slope rating. The course rating sets the expected score for a scratch golfer, and the slope scales the result for a bogey golfer on that course. The index is the average of your best differentials, with a small adjustment when only three to six rounds are available.
Example
Shooting 85 on a course rated 72.0 with a slope of 113 gives a differential of (85 − 72) × 113 ÷ 113 = 13.0. On a harder course with a slope of 130, the same score gives 11.3, because the course is rated more difficult relative to a bogey golfer.
Formula
(score − course rating) × 113 ÷ slopeaverage of the lowest qualifying differentials3 rounds: lowest − 2.0; 4: lowest − 1.0; 6: lowest 2 − 1.0No adjustment applies from five rounds upward in the simplified table used here.
Reading the Results
Handicap Index
A portable measure of playing ability, expressed to one decimal place. It is not the number of strokes you receive on a particular course; the course handicap converts it for that layout.
Differential
One round’s performance normalised for course difficulty. Differentials are the raw material of the index, which is why the calculator shows each one before adding it.
Sources and References
The R&A and USGA — World Handicap System: Rules of Handicapping
Score differential and Handicap Index calculation
The governing rules for the differential formula and the best-round table.
USGA — Course Rating and Slope Rating
Definitions of course rating and slope
Explains why a harder course produces a lower differential for the same score.
The R&A — WHS Guidance
Minimum rounds and adjustment table
Confirms that at least three 18-hole scores are needed before an index is issued.
References identify the method or data behind this calculator. Where a standard or tariff changes, the current edition applies, and the assumptions stated above take precedence over a remembered figure.
Frequently Asked Questions
How many rounds do I need for a handicap?
At least three 18-hole scores under the World Handicap System. With three or four rounds the index uses only your lowest differential plus an adjustment; from 20 rounds it uses the best eight.
Why is my differential lower on a harder course?
Because the slope rating divides the score difference. A course with a slope of 130 is harder for a bogey golfer than one rated 113, so the same raw score represents a better relative performance and produces a smaller differential.
Is course handicap the same as Handicap Index?
No. The index is your portable baseline. The course handicap adjusts it for the tees and course you are playing, using the slope rating, so you receive more or fewer strokes depending on the layout.
Does this use adjusted gross score?
It expects the adjusted gross score, which caps very high hole scores under net double bogey. If you enter a raw score with a disastrous hole, the differential will be slightly higher than the official one.