How to use it
- Type one line per round in Your rounds, the most recent first. Each line needs the adjusted gross score, the course rating and the slope rating, and a PCC adjustment if there is one.
- Enter the Slope rating, the Course rating and the Par of the course you play to get the Course handicap.
- Read the Handicap Index at the top and the Course handicap under it. The Score differentials table shows which rounds count.
- Open How the result is worked out to see each step of the calculation.
How the handicap is worked out
A score differential puts a round on a common scale, so a round on an easy course and one on a hard course can be compared. The formula scales the score by 113 divided by the slope rating of the tees played.
The Handicap Index is the average of the lowest differentials from the most recent 20 rounds, rounded to one decimal place. The course handicap then converts the index into the strokes you receive on a particular course.
Score differential = 113 ÷ slope rating × (adjusted gross score − course rating − PCC adjustment)
Handicap Index = average of the lowest differentials of the last 20 rounds (fewer rounds: see the table below), to one decimal place
Course handicap = Handicap Index × slope rating ÷ 113 + (course rating − par), to a whole number- Each score differential is rounded to the nearest tenth before the differentials are averaged.
- The PCC adjustment (the playing conditions calculation) records whether the conditions on the day were different from normal. Its values are -1, 0, +1, +2 or +3. A round without an adjustment counts as 0.
Handicap Index with fewer than 20 rounds
With three to nineteen rounds, a table sets how many of the lowest differentials are averaged and whether an adjustment is added to the average. Three rounds are the least that give an index. From 20 rounds the lowest eight of the most recent 20 are averaged, with no adjustment.
The table is the one in the Wikipedia article on the World Handicap System. The R&A rules (rule 5.2a) refer to a table of this kind, but the table itself is an image on their page, so check it there.
| Rounds | Lowest differentials used | Adjustment to the average |
|---|---|---|
| 3 | 1 | −2.0 |
| 4 | 1 | −1.0 |
| 5 | 1 | 0 |
| 6 | 2 | −1.0 |
| 7 or 8 | 2 | 0 |
| 9 to 11 | 3 | 0 |
| 12 to 14 | 4 | 0 |
| 15 or 16 | 5 | 0 |
| 17 or 18 | 6 | 0 |
| 19 | 7 | 0 |
| 20 or more | 8 of the most recent 20 | 0 |
What this calculator does not cover
- Exceptional score reductions, Handicap Committee adjustments and the soft and hard caps that limit how fast an index can rise are not calculated. The R&A rules set out when each one applies.
- Playing handicaps, which apply a handicap allowance to the course handicap for a competition format, are not calculated. The tool gives the course handicap only.
- Nine-hole scores need a method that this calculator does not include. Enter 18-hole rounds, or ask your club how to combine nine-hole scores.
- Your official handicap comes from your club or national association, which may apply its own settings within the system.
Worked example: 8 rounds on a course with slope 128
The eight rounds on the page, newest first, give the differentials 14.9, 12.2, 16.5, 12.4, 13.7, 16.7, 13.7 and 14.8. The first is 113 ÷ 125 × (88 − 71.5 − 0) = 14.9.
With eight rounds the table averages the lowest two, 12.2 and 12.4, which gives 12.3 with no adjustment. The Handicap Index is 12.3.
On a course with slope 128, course rating 72.3 and par 72, the course handicap is 12.3 × 128 ÷ 113 + (72.3 − 72) = 14.23, which rounds to 14.
| Round | Differential | Counts |
|---|---|---|
| 1 | 14.9 | Not used |
| 2 | 12.2 | Used |
| 3 | 16.5 | Not used |
| 4 | 12.4 | Used |
| 5 | 13.7 | Not used |
| 6 | 16.7 | Not used |
| 7 | 13.7 | Not used |
| 8 | 14.8 | Not used |
Frequently asked questions
What is a score differential?
A score differential is one round put on the common scale of the system: the adjusted gross score less the course rating and any PCC adjustment, scaled by 113 divided by the slope rating. It lets rounds on different courses be compared.
Why does the index use only eight of my last 20 rounds?
The rules aim for a Handicap Index that represents demonstrated ability, so the lowest of the most recent 20 differentials are averaged. Using the best eight means one bad day does not raise the index much.
What if I have fewer than 20 rounds?
The table for fewer rounds sets how many of the lowest differentials to average and whether an adjustment is added. Three rounds are the least that give an index, and the calculator still shows the differentials below that.
What is the PCC adjustment, and do I have to enter it?
The PCC is the playing conditions calculation, which checks whether conditions on the day differed from normal. Its value is a whole number from -1 to +3. Type it on that round's line if you know it; leave it out to count it as 0.
Why is my course handicap different from my Handicap Index?
The course handicap scales the index by the slope of the tees you play and adds the course rating less par. A course with a high slope or a rating above par gives you a different number of strokes from the index alone.
Is the result my official handicap?
No. An official index is kept by your club or national association under the rules. This calculator shows how the rules turn the rounds you type into a handicap figure.
Sources
- R&A, The Rules of Handicapping, Rule 5: calculation of a score differential, of the Handicap Index, and the PCC adjustment (rules 5.1, 5.2, 5.6)
- R&A, The Rules of Handicapping, Rule 6: Course Handicap and Playing Handicap calculation
- Wikipedia: World Handicap System (score differential, Handicap Index, the table for fewer than 20 scores, course handicap)
Figures and text last checked on Tuesday, November 10, 2026.