How is a Score Differential calculated?

Under Rule 5.1 of the 2024 Rules of Handicapping, an 18-hole Score Differential is:

(113 ÷ Slope Rating) x (adjusted gross score - Course Rating - PCC adjustment)

It is rounded to the nearest tenth, with .5 rounded up. The PCC adjustment ranges from -1.0 to +3.0 (see the PCC question). Your adjusted gross score is your gross score with any hole scores above the maximum (net double bogey, or par + 5 before you have a Handicap Index) reduced to that maximum.

Example: an adjusted gross score of 85 on tees with Course Rating 71.0 and Slope Rating 125, with a PCC adjustment of 0, gives 113 ÷ 125 x (85 - 71.0) = 0.904 x 14 = 12.7.

• Scores below the Course Rating: the differential is negative and rounds upward towards 0. -1.54 and -1.55 round to -1.5, and -1.56 rounds to -1.6.
• 9-hole scores: the 9-hole differential uses the 9-hole Slope Rating, Course Rating and 0.5 x the PCC adjustment. It is combined with your expected score over 9 holes to make an 18-hole differential.