The slope rating is the USGA mark that indicates the measurement of the relative difficulty for a bogey golfer compared to the course rating. Slope rating is computed from the difference between the bogey rating and the course rating. The lowest slope rating is 55 and the highest is 155. The average slope rating is 113. To compute the handicap strokes from a given set of tees on a specific course with a slope of "s" given a handicap index of "h," the following formula is used: (s/113)*h rounded to the nearest integer.
Example: A male golfer plays a course with Slope Rating 126, and Course Rating 72.5. Per the formula, compute 126 / 5.381 + 72.5 = 95.9 - which predicts the bogey golfer's average of his ten best (out of twenty) scores would be approximately 95.9 from this particular set of tees.
Read more about this topic: Handicap (golf)