Calculate your golf handicap index from your round scores and course/slope ratings.
Enter your recent rounds. Each round needs a score, course rating, and slope rating.
Score
Course Rating
Slope Rating
Differential
Remove
9.1
8.0
10.9
8.8
8.5
Your Handicap Index
7.9index
Rounds entered5
Best differential8.0
Average differential (best rounds)8.2
Handicap index is calculated from your best 8 of 20 rounds (or proportionally fewer if you have fewer than 20). Each round's differential is (Score − Course Rating) × 113 ÷ Slope Rating, then the index is the average differential × 0.96.
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What is the Golf Handicap Calculator?
A golf handicap index is a number that represents your golf ability, adjusted for course difficulty. The calculator takes your round scores along with each course's rating and slope, computes a differential for each round, then averages the best differentials using the standard formula: (average of best rounds) × 0.96. This index lets golfers of different abilities compete fairly.
How it works
For each round you enter, the calculator computes a differential: (Your Score − Course Rating) × 113 ÷ Slope Rating. It then ranks all differentials and selects the best 8 out of 20 rounds (or proportionally fewer if you have fewer than 20). The average of these best differentials is multiplied by 0.96 to yield your handicap index.
Handicap Index = (Average of Best 8 of 20 Differentials) × 0.96, where Differential = (Score − Course Rating) × 113 ÷ Slope Rating
The formula normalises scores across different courses: a 73 on a par-70 course with slope 130 is compared fairly to an 80 on a par-72 course with slope 120. The 113 constant anchors the calculation to a scratch golfer's 80% hit rate. The 0.96 multiplier ensures the index is conservative—your handicap reflects your typical best play, not every round.
Examples
Input
Result
Notes
Round 1: Score 82, Course Rating 71.5, Slope 130
Differential = (82 − 71.5) × 113 ÷ 130 = 9.1
One-round example; handicap index requires multiple rounds and uses best differentials only.
5 rounds with differentials [9.1, 7.2, 10.3, 8.8, 8.0]
Best 2 of 5 = [7.2, 8.0], Average = 7.6, Handicap Index = 7.6 × 0.96 = 7.3
With 5 rounds, the best 2 are used (40% of 5). Fewer rounds = proportionally fewer best rounds used.
20 rounds with best 8 differentials averaging 6.5
Handicap Index = 6.5 × 0.96 = 6.2
Full dataset: best 8 of 20 (40%) are selected. Index of 6.2 means you're playing roughly 6 strokes under par on an average course.
How to use the Golf Handicap Calculator
Gather your recent rounds—score, course rating, and slope rating for each.
Enter the data row by row: score in the first column, course rating in the second, slope in the third.
The calculator instantly computes each round's differential.
It identifies your best rounds (8 of 20, or proportionally fewer) and averages them.
Multiply by 0.96 to get your official handicap index.
Use this index in tournaments or to set personal golf goals.
Benefits
Fair comparison across courses of different difficulty.
Standardised formula used by golf clubs and tournaments worldwide.
Instant calculation with automatic differential ranking.
Helps track improvement over time as your index changes.
Accounts for course slope and rating variation automatically.
Free and private—no account, no login required.
Tips & common mistakes
Common mistakes
Forgetting to look up course rating and slope for your round—always note these at the pro shop or scorecard.
Entering 'par' instead of the actual course rating—they're different; par is the number of strokes an expert should take; rating is the expected score for a scratch golfer.
Using only one round to estimate handicap—the formula requires multiple rounds (ideally 20) to be reliable.
Tips
Save your recent scorecards; they contain course rating and slope rating, needed for accurate calculation.
Track your handicap index monthly or quarterly to see if your game is improving.
Check if your club publishes official handicap indexes; this tool is a quick way to estimate between updates.
Frequently asked questions
What's the difference between handicap index and course handicap?
Handicap index is your standardised ability number (e.g., 6.2) and travels with you to any course. Course handicap is index adjusted for *that specific course's* slope and rating, used to determine your gross-to-net score in tournaments. This calculator gives you the index.
Why does the calculator only use the best 8 rounds?
The USGA formula assumes that your best rounds reflect your true ability, while off days skew the average. Using your best 8 of 20 (40%) gives a conservative, achievable index.
Can I use rounds from different courses?
Yes. The beauty of the formula is that it normalises for course difficulty (rating and slope), so a score on a hard course and a score on an easy course are compared fairly.
What if I have fewer than 8 rounds?
The calculator uses a proportional approach: if you have 5 rounds, it uses the best 2 (40%). The more rounds you enter, the more reliable your handicap index becomes.
Is my data saved or shared?
No. This calculator runs entirely in your browser. Your rounds are not sent to any server, stored, or logged. Refresh the page and your data is gone—enter it again if needed.
Can negative handicap indexes happen?
Yes. A negative handicap (e.g., −2.5) means you play *better* than scratch golfers on average. It's rare and marks an accomplished golfer.