- List your 20 most recent rounds.
- Apply equitable stroke control* to your hole-by-hole results in those rounds to determine an adjusted score.
- Subtract the course rating for each course from your adjusted score to determine a differential for each round.
- To factor in the difficulty of each course, calculate a slope rating adjustment by dividing 113 by the designated slope.**
- Multiply the differential by the slope rating adjustment.
- Multiply that figure by 0.96.
- Rank your 20 results from lowest to highest.
- Calculate the average of your 10 lowest results from those 20 most recent rounds. This figure is your handicap index - a measure of what your handicap would be at a course of average difficulty.
- At any actual course, use the handicap index conversion chart to see what your handicap is at that particular course for your particular index.
*Equitable stroke control is intended to keep a few bad holes from excessively raising a player's handicap index. It sets maximums for the score you can have on any single hole when you're preparing your rounds to be included in your handicap. The maximums, which depend on your handicap at the particular course, are as follows:
**113 is the slope rating assigned to a course of exactly average difficulty.
-- All text excerpted from "A Disorderly Compendium of Golf," by Lorne Rubenstein and Jeff Neuman (Workman, $13.95)