Golf Handicap Calculator
Score Differential Calculator
Score Differential
Note: Your official USGA Handicap Index averages your best score differentials from your last 20 rounds (with adjustments) — this tool calculates a single round's differential, one building block of that calculation.
Ready for Calculation
Enter your score, course rating, and slope rating to calculate the score differential.
Understanding Golf Score Differentials
A score differential adjusts your raw score for the specific difficulty of the course you played, using its Course Rating and Slope Rating. Differentials from multiple rounds are what ultimately combine to form your official Handicap Index.
Course Rating
Course Rating represents the expected score for a scratch (zero-handicap) golfer on that course, usually close to par.
Slope Rating
Slope Rating measures relative difficulty for a bogey golfer compared to a scratch golfer, ranging from 55 (easiest) to 155 (hardest), with 113 as the average.
The Formula
Score Differential = (Adjusted Gross Score − Course Rating) × 113 ÷ Slope Rating. The constant 113 is the average Slope Rating, used to normalize every course to a common baseline.
Building the Full Index
The official World Handicap System averages your best 8 differentials from your most recent 20 rounds to calculate your Handicap Index.
Key Takeaways
- Adjusted Gross Score: Official handicap calculations use a score adjusted with "Equitable Stroke Control" caps per hole, not necessarily your raw total.
- Course-Specific: A round on a harder course (higher slope) produces a lower differential for the same raw score than an easier course.
- Official Index Requires History: A true, official Handicap Index requires a certified handicap service tracking multiple rounds over time.