Golf Handicap Calculator – Differential, Handicap Index And Course Handicap
This Golf Handicap Calculator gives you several connected views of your playing ability. You can calculate handicap differential from a single round, estimate your handicap index from your best differentials, convert index to course handicap for a specific set of tees, and then apply a competition allowance to find your playing handicap.
Handicap Differential – Score, Rating And Slope
A handicap differential is a single-round performance number that takes the difficulty of the course into account. A simplified version of the World Handicap System formula is:
Differential = (Adjusted Gross Score − Course Rating) × 113 ÷ Slope Rating
Adjusted gross score is your score after applying any required adjustments. Course rating describes the expected score for a scratch golfer, while slope rating measures how much harder the course plays for a bogey-level player compared with a scratch player. The constant 113 is a standard reference slope.
Handicap Index – Averaging Your Best Differentials
Your handicap index is built from your most recent differentials, not from a single round. The modern World Handicap System usually looks at the last 20 rounds and averages the lowest 8 differentials. When fewer differentials are available, a different number of scores is used. A common reference table is:
- 3–5 scores: lowest 1 differential
- 6–8 scores: lowest 2 differentials
- 9–11 scores: lowest 3 differentials
- 12–14 scores: lowest 4 differentials
- 15–16 scores: lowest 5 differentials
- 17–18 scores: lowest 6 differentials
- 19 scores: lowest 7 differentials
- 20 scores: lowest 8 differentials
The handicap index tab in this calculator follows that style. It filters out blank entries, sorts the remaining differentials from lowest to highest, selects the correct number from the top of the list and averages them to produce an index estimate.
Course Handicap – Adjusting For The Tees You Play
Handicap index is a portable measure of ability; course handicap converts that index into the number of strokes you receive on a particular course from a particular set of tees. A World Handicap System style formula is:
Course Handicap = Handicap Index × (Slope Rating ÷ 113) + (Course Rating − Par)
The first term scales your index by the relative difficulty of the tees you are playing. The second term adjusts for the difference between course rating and par so that handicaps travel more fairly between courses with different ratings but similar par values.
Playing Handicap – Applying An Allowance
Many formats, such as stroke play, Stableford or fourball match play, apply an allowance percentage to course handicap. For example, a competition might state that players receive 95% of their course handicap in stroke play. The calculator’s playing handicap tab uses:
Playing Handicap = Course Handicap × (Allowance ÷ 100)
You can choose how to round the result: to the nearest whole number, always down or always up, depending on local rules. The playing handicap is what you would usually write on the scorecard for handicap strokes.
Putting It All Together
These four views work together as a mini handicap toolkit:
- Use the differential tab to turn a single round into a course-adjusted performance number.
- Enter several differentials into the index tab to see an index based on your best scores.
- Convert that index to a course handicap for the specific tees you are about to play.
- Apply the competition allowance to convert course handicap into playing handicap.
Actual official handicaps are controlled by national associations and golf clubs. This tool follows typical formulas for learning and planning, and is not a replacement for an authorised handicap service.
Formula Summary
- Differential: (Adjusted Score − Course Rating) × 113 ÷ Slope Rating
- Handicap Index: Average of a set number of lowest differentials
- Course Handicap: Index × (Slope ÷ 113) + (Course Rating − Par)
- Playing Handicap: Course Handicap × (Allowance ÷ 100)
Golf Handicap Calculator – Frequently Asked Questions
Is this calculator the same as an official handicap service?
This page follows typical World Handicap System style formulas, but it does not replace an official handicap issued by a club or golfing authority. Use it as an educational guide and planning tool alongside authorised systems.
What is slope rating?
Slope rating expresses how much more difficult a course is for a bogey-level player than for a scratch player. A slope of 113 is considered standard. Higher slopes mean a course is relatively more challenging for most golfers.
Why does the index calculation ignore some differentials?
The handicap system focuses on your best scoring potential rather than every round. That is why only a certain number of the lowest differentials are averaged, with the exact number depending on how many scores you have posted.
Can I use nine-hole scores?
Official systems have specific rules for combining nine-hole rounds into differentials. This calculator works with full differentials, so if nine-hole scores are converted to full differentials first, you can input them like any other round.
How should I round handicaps for competition?
Different organisations may require different rounding rules. The course handicap and playing handicap tabs let you choose between rounding to the nearest whole number, always down or always up so that you can match your local competition conditions.