Direct answer: a round is converted to a Score Differential using adjusted gross score, Course Rating, Slope Rating and PCC. A full 20-score record averages the lowest eight differentials. Course Handicap then adjusts the index for the tees being played. The old 0.96 multiplier is not part of the current World Handicap System.

1. Calculate a round differential

Score Differential = (113 ÷ Slope Rating) × (Adjusted Gross Score − Course Rating − PCC)
Example: adjusted gross score 85, Course Rating 71.4, Slope Rating 125 and PCC 0.
(113 ÷ 125) × (85 − 71.4) = 12.2944, rounded to 12.3.

Course Rating represents the expected score for a scratch player under normal conditions. Slope Rating expresses relative difficulty for a bogey player compared with a scratch player; 113 is the standard-slope reference. PCC is produced by the authorised daily process and can adjust the calculation for unusually easy or difficult conditions.

2. Select the required differentials

Differentials in recordCalculation used
3Lowest 1, minus 2.0
4Lowest 1, minus 1.0
5Lowest 1
6Average lowest 2, minus 1.0
7–8Average lowest 2
9–11Average lowest 3
12–14Average lowest 4
15–16Average lowest 5
17–18Average lowest 6
19Average lowest 7
20Average lowest 8

The result is rounded to one decimal. Official systems may then apply safeguards including exceptional-score reductions, soft and hard caps, committee adjustments and treatment of incomplete or 9-hole scores.

3. Calculate Course Handicap

Course Handicap = Handicap Index × (Slope Rating ÷ 113) + (Course Rating − Par)

Course Handicap converts the index to the tees being played. Playing Handicap can then apply a competition allowance to the unrounded Course Handicap according to the format or competition conditions.

Example: index 12.4, Slope 128, Course Rating 71.4 and par 72.
12.4 × (128 ÷ 113) + (71.4 − 72) = 13.445..., which rounds to a Course Handicap of 13.

Adjusted gross score and hole limits

For a player with an established index, the usual maximum hole score for posting is net double bogey: par + two strokes + any handicap stroke received on the hole. Different treatment applies when establishing an initial index. Use the adjusted score produced under the official rules rather than simply entering an unadjusted card total.

Why ToolBullet calls its result an estimate

Only an authorised association or delegated club can issue and maintain an official Handicap Index. A standalone browser tool cannot verify PCC, complete scoring history, exceptional-score adjustments, expected-score calculations or committee decisions. ToolBullet reproduces the published arithmetic for education and independent checking.

Calculate a round differential, a 3–20 score estimate and a Course or Playing Handicap.

PCC, caps and exceptional-score safeguards

The Playing Conditions Calculation is not a number a player should invent after the round. It is produced by the authorised handicapping process from eligible scores for that course and day, and the resulting PCC value is used in the Score Differential. Official records can also apply exceptional-score reductions and soft or hard caps linked to a Low Handicap Index. These safeguards are why recreating the visible arithmetic in a browser is useful for checking and education but is not identical to maintaining an official record.

Keep the tees and score basis consistent

Course Rating, Slope Rating and par must come from the specific tees played. Mixing a score from one set of tees with ratings from another changes both the differential and Course Handicap. The adjusted gross score should already reflect the applicable maximum-hole-score procedure. Keep the original card and rating information when checking a result so each input can be traced.

How it works and sources

World Handicap System method reviewed 7 July 2026. ToolBullet uses these sources to explain the method and its limits; it does not replace coaching, medical advice or official governing-body records.