### 5.1 Calculation of a Score Differential

#### 5.1a For an 18-hole Score

An 18-hole Score Differential is calculated as follows and rounded to the nearest tenth, with .5 rounded upwards:

 Score Differential = (113 ÷ Slope Rating) x (adjusted gross score – Course Rating – PCC adjustment)

Note: The PCC adjustment ranges from -1.0 to +3.0 (see Rule 5.6 Playing Conditions Calculation).

#### 5.1b For a 9-hole Score

 If a player submits a 9-hole score, an 18-hole Score Differential must be created by combining two 9-hole Score Differentials. A 9-hole Score Differential is calculated as follows using 50% of the playing conditions calculation (PCC) adjustment for the day:
 Score Differential = (113 ÷ 9-hole Slope Rating) x (9-hole adjusted gross score – 9-hole Course Rating – (0.5 x PCC adjustment))

Notes:

1. A 9-hole Score Differential remains unrounded until after it has been combined with a second 9-hole Score Differential and an 18-hole Score Differential is calculated.
2. For the calculation of a 9-hole Course Handicap, see Rule 6.1b For a 9-hole Round.
3. An 18-hole PCC adjustment ranges from -1.0 to +3.0 (see Rule 5.6 Playing Conditions Calculation).

An 18-hole Score Differential is then created by either:

• Combining a 9-hole Score Differential with an existing 9-hole Score Differential, or
• Combining a 9-hole Score Differential with the next 9-hole Score Differential that is calculated.

Note: An uncombined 9-hole score will be discarded when it becomes older than the twentieth Score Differential in the scoring record.

#### 5.1c Rounding of Minus Score Differentials

When an adjusted gross score calculates lower than the Course Rating, this results in the Score Differential being a negative number. Where this occurs, rounding is made upward towards 0. For example:

• When a Score Differential is calculated as -1.54, it is rounded to -1.5
• When a Score Differential is calculated as -1.55, it is rounded to -1.5
• When a Score Differential is calculated as -1.56, it is rounded to -1.6