Handicaps and scoring
Parful runs thisHandicap Index®
Also called Golf handicap, WHS index, Handicap number.
A Handicap Index® is a measure of your demonstrated ability, carried between courses. Under the World Handicap System™ it is the average of the best 8 Score Differentials™ in your most recent 20 rounds, and it means nothing until it is converted to a Course Handicap™ for the tees you are playing.
- What it measures
- Demonstrated ability, not average score
- Calculated from
- The best 8 of your last 20 Score Differentials™
- Minimum to hold one
- 3 acceptable rounds
- Range
- From +10 (a plus player) to 54
- Decimal places
- One, for example 12.4
- On Parful
- Synced, entered by the club, self-declared, estimated after 3 rounds, or absent
What the index actually measures
A Handicap Index® is not your average score. It is a measure of what you are capable of when you play well, which is why it uses your best rounds and ignores the rest. Take a golfer who shoots between 88 and 104 on a par 72. Their average is somewhere near 95, but their index is built from the low end of that spread, so it lands nearer 16 than 23. This is deliberate: a handicap is meant to let two golfers compete on equal terms when both play to their potential, not to reward whoever is most inconsistent.
The number is portable. It does not belong to a course, which is why it needs converting before it can put strokes on a card. That conversion is the Course Handicap™, and it is a separate page.
Best 8 of the last 20
Every acceptable round produces one Score Differential™: how far that round stood from the difficulty of the tees played. Your index is the average of the lowest 8 differentials among your most recent 20 rounds, rounded to one decimal. A twenty-first round pushes the oldest one out of the window, so the index moves as your recent form moves and old rounds stop counting entirely.
Because only the best 8 count, a bad round does not raise your index. It occupies a slot in the 20 without contributing, and it pushes out a round that may have been good. That is the only way a poor score can affect you, and it takes time.
While the index is settling
A golfer with fewer than 20 rounds cannot take the best 8, so the World Handicap System™ uses a smaller sample with a downward adjustment that shrinks as evidence accumulates. Three rounds is the minimum for an index at all.
- 3 rounds: the lowest 1 differential, minus 2.0
- 4 rounds: the lowest 1, minus 1.0
- 5 rounds: the lowest 1, with no adjustment
- 6 rounds: the lowest 2, minus 1.0
- 7 to 8 rounds: the lowest 2
- 9 to 11 rounds: the lowest 3
- 12 to 14: the lowest 4. 15 to 16: the lowest 5. 17 to 18: the lowest 6. 19: the lowest 7. 20 or more: the lowest 8
Where Parful gets your index
A member on a Parful roster carries their index from one of several places, and the club can see which. A linked member has a handicap ID on file and their index arrives by sync when the club has that turned on. A manual member carries whatever the club last entered. A member with neither can declare their own on their profile, which never overwrites the club roster. A player with enough rounds recorded on Parful gets an estimated index after 3 acceptable rounds, marked as estimated rather than official.
A guest or walk-up who has no index at all is recorded as NH, no handicap, and NH is never quietly treated as scratch. Every change to a roster handicap writes a revision and an audit entry, so a club can always answer the question of who changed a number and when.
Worked example
A worked example: an index from 20 rounds
Maria has 20 acceptable rounds in her window. Their Score Differentials™, sorted low to high, are below. The best 8 are counted and averaged.
| Rank | Differential | Counted? |
|---|---|---|
| 1 to 4 | 11.8, 12.3, 12.9, 13.1 | Yes |
| 5 to 8 | 13.4, 13.6, 14.0, 14.3 | Yes |
| 9 to 12 | 14.9, 15.2, 15.8, 16.1 | No |
| 13 to 16 | 16.4, 17.0, 17.7, 18.2 | No |
| 17 to 20 | 19.1, 20.4, 22.6, 25.9 | No |
- Maria's worst round, a 25.9 differential, changes nothing except that it occupies a slot in the 20.
- If her next round produces a differential of 11.0, it enters the counted 8 and pushes out the 14.3. The index falls to 13.1.
Common variants
- The soft cap and hard cap
- The World Handicap System™ limits how fast an index can rise above a player's Low Handicap Index™ from the last year: increases beyond 3.0 are suppressed, and 5.0 is the ceiling. Parful records a low index but does not apply the caps in its own calculation.
- Playing Conditions Calculation
- The WHS adjusts differentials on days when the whole field scored abnormally. Parful always uses a value of zero, so a windy day is not compensated for in its own differentials.
- Nine-hole rounds
- The WHS combines two nine-hole scores into one 18-hole differential. Parful scores nine-hole rounds but does not post them for handicap yet.