Golf / Score records
Golf Handicap Calculator: Differentials and Course Handicap
Enter adjusted 18-hole scores or existing score differentials in chronological order. Calculate the basic index from the latest 20 and the fewer-than-20 adjustments, then convert an index to course handicap.
Golf Handicap Calculator: Differentials and Course Handicap: Rounds each score differential to one decimal, retains the latest 20, and averages the lowest number required by Rule 5.2a or the lowest 8 for 20 scores. It applies the initial-record adjustment and maximum index of 54.0. The result is a basic index before exceptional-score reductions, low-index caps and committee adjustments. Runs 100% locally in your browser with zero server file uploads.
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Enter adjusted gross scores: applying net double bogey and other hole-score adjustments is your responsibility. This calculates the basic index only; exceptional-score reductions, low-index caps and committee adjustments need your official scoring record. Use an official index for competition.
| Record | Differential |
|---|---|
| 1 | 8 |
| 2 | 10 |
| 3 | 12 |
Selected lowest differentials: 8
Fewer-than-20 adjustment table
| Scores available | Lowest scores used | Adjustment |
|---|---|---|
| 3 | 1 | -2 |
| 4 | 1 | -1 |
| 5 | 1 | 0 |
| 6 | 2 | -1 |
| 7–8 | 2 | 0 |
| 9–11 | 3 | 0 |
| 12–14 | 4 | 0 |
| 15–16 | 5 | 0 |
| 17–18 | 6 | 0 |
| 19 | 7 | 0 |
| 20 or more | 8 | 0 |
Each differential is (113 ÷ slope) × (adjusted score − course rating − PCC), rounded to one decimal. The record keeps the latest 20 scores and averages the required lowest differentials. Course handicap is index × slope ÷ 113 + course rating − par, rounded to a whole stroke. This page uses 18-hole scores.
Score differential and basic index
USGA and R&A Rules of Handicapping, Rules 5.1, 5.2 and 5.3. An 18-hole differential is (113 ÷ slope) × (adjusted gross score − course rating − PCC). Rule 5.2 specifies the fewer-than-20 table and the average of the best 8 of the last 20; the maximum index is 54.0. Official R&A rule: https://www.randa.org/en/roh/the-rules-of-handicapping/rule-5 . USGA rules: https://rules.usga.org/rules-of-handicapping/
Course handicap and adjusted scores
Rules 6.1 and 3.1: course handicap = index × slope ÷ 113 + (course rating − par), rounded to a whole stroke. Apply net double bogey and other required adjustments before entering scores. Official rules: https://www.randa.org/en/roh/the-rules-of-handicapping/rule-6 ; https://www.randa.org/en/roh/the-rules-of-handicapping/rule-3
How to use it
- Enter one adjusted 18-hole round per line, oldest first, or choose existing differentials.
- Read the latest differential, selected lowest values and calculated index.
- Enter the course slope, rating and par; optionally supply your official index.
Privacy & limitations
The score record stays in your browser and is not uploaded or saved.
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Frequently asked questions
Which scores should I enter?
Use adjusted gross 18-hole scores. You are responsible for net double bogey and other hole-score adjustments. Each line contains adjusted score, course rating, slope and the official PCC. Nine-hole scores are outside this page's scope.
What happens with fewer than 20 scores?
Three scores use the lowest 1 minus 2; four use the lowest 1 minus 1; five use the lowest 1; six use the lowest 2 minus 1; seven or eight use 2; nine to eleven use 3; twelve to fourteen use 4; fifteen or sixteen use 5; seventeen or eighteen use 6; nineteen use 7.
Is this an official Handicap Index?
No. An official index also needs an authorised scoring record and the relevant safeguards, exceptional-score reductions and committee adjustments. Enter your official index in the optional field when calculating course handicap for competition.
How do I enter a plus handicap?
Enter a plus index as a negative number, such as -2.0. The result displays Plus 2.0. Course handicap uses the signed number. Course handicap is not the same as playing handicap when a competition applies an allowance.
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