Course Slope Rating Calculator: Measure Course Difficulty
Estimate a course's slope rating by entering the bogey player and scratch player scores below.
Enter Player Performance Data
A bogey golfer typically scores about 90 on 18 holes
A scratch golfer typically scores about 72 on 18 holes
The expected score for a scratch golfer
List of the Top 10 Best Golf Accessories:
Understanding Course Slope Rating
Slope rating measures the relative difficulty of a golf course for bogey golfers compared to scratch golfers. The standard slope is 113, with higher numbers indicating greater difficulty for average players.
How to Use This Calculator
Follow these steps to estimate a course's slope rating:
- Enter the bogey golfer's adjusted score (typically around 90 for 18 holes)
- Enter the scratch golfer's adjusted score (typically around 72 for 18 holes)
- Input the official course rating
- Click "Calculate Slope Rating"
The Slope Rating Formula
The USGA slope rating formula is:
Slope Rating = (Bogey Rating - Course Rating) × 5.381
Where:
- Bogey Rating represents the expected score for a bogey golfer (20 handicap)
- Course Rating represents the expected score for a scratch golfer (0 handicap)
- 5.381 is a constant that scales the result to the standard slope of 113
Interpreting Slope Ratings
| Slope Range | Difficulty Level | Description |
|---|---|---|
| 55-80 | Very Easy | Extremely forgiving course with minimal hazards |
| 81-95 | Easy | Few obstacles, good for beginners |
| 96-105 | Average | Moderate challenge for most players |
| 106-115 | Difficult | Presents significant challenge to bogey golfers |
| 116-130 | Very Difficult | Extremely challenging for average players |
| 131-155 | Extreme | Among the most difficult courses in the world |
Components of Course Rating
Obstacle Factors
Course raters evaluate these 10 factors (rated 0-10):
- Topography
- Fairway width
- Green target size
- Rough and recovery difficulty
- Bunker placement
- Out of bounds/water hazards
- Trees and their impact
- Green surface difficulty
- Psychological factors
- Overall walkability
Effective Playing Length
Adjusted for these factors:
- Roll: How far the ball rolls on fairways
- Elevation changes
- Forced layups
- Doglegs
- Prevailing wind
- Altitude
Frequently Asked Questions
What's the difference between course rating and slope rating?
Course rating indicates difficulty for scratch golfers (absolute measure), while slope rating indicates relative difficulty for bogey golfers compared to scratch golfers.
Why is 113 the standard slope rating?
113 represents the average difficulty. It was chosen mathematically as the point where a bogey golfer would need exactly their handicap to play to the course rating.
How accurate is this calculator compared to official ratings?
This provides a good estimate, but official ratings involve detailed on-course evaluation by trained raters considering all obstacle factors.
Can slope rating be different for different tees?
Yes, each set of tees has its own slope rating as distance and obstacles affect players differently from various starting points.
How Course Ratings Are Determined Officially
The Rating Process
- A team of trained USGA raters walks the course
- They evaluate all 10 obstacle factors for each hole
- They calculate effective playing length adjustments
- They determine bogey and scratch player strategies
- Mathematical formulas convert evaluations to ratings
- Ratings are peer-reviewed and validated
Rating Team Composition
- Typically 2-4 trained raters
- Includes both scratch and bogey golfers
- Must complete USGA rating training
- Often volunteers from local golf associations
Slope Rating in Handicap Calculation
Course Handicap Formula
Course Handicap = Handicap Index × (Slope Rating ÷ 113)
Example Calculations
| Handicap | Slope 113 | Slope 130 | Slope 95 |
|---|---|---|---|
| 10 | 10 | 12 | 8 |
| 18 | 18 | 21 | 15 |
| 5 | 5 | 6 | 4 |