Activities Sports & Athletics How Is Golf Handicap Index Calculated? Here's the Formula Share PINTEREST Email Print Vichien Petchmai/Getty Images Sports & Athletics Golf Basics History Gear Golf Courses Famous Golfers Golf Tournaments Baseball Basketball Bicycling Billiards Bodybuilding Bowling Boxing Car Racing Cheerleading Cricket Extreme Sports Football Gymnastics Ice Hockey Martial Arts Professional Wrestling Skateboarding Skating Paintball Soccer Swimming & Diving Table Tennis Tennis Track & Field Volleyball Other Activities Learn More By Brent Kelley Brent Kelley is an award-winning sports journalist and golf expert with over 30 years in print and online journalism. our editorial process Brent Kelley Updated November 04, 2019 The golf handicap calculation is something that most golfers never have to worry about. If you carry an official USGA Handicap Index, the calculation is performed for you by other people (or, far more likely, by a computer). You can also get an unofficial estimate of your handicap by using a golf handicap calculator. But you want the nuts and bolts of the handicap formula, don't you? You want to know the math behind figuring handicaps. OK, you asked for it, you got it. What You'll Need for the Handicap Formula What numbers do you have to have in order to perform the handicap index calculation? The formula requires the following: Your scores: a minimum of five and up to 20. And these are your adjusted gross scores (meaning they follow the equitable stroke control per-hole maximums).The USGA course ratings of the golf courses you've played.The USGA slope ratings of the courses you've played. Have all that? OK, we're ready to get into the math of the handicap formula. Step 1 In Handicap Formula: Calculate the Differentials Using your adjusted gross scores, the course ratings, and slope ratings, Step 1 is calculating the handicap differential for each round entered using this formula: (Score - Course Rating) x 113 / Slope Rating For example, let's say your score is 85, the course rating 72.2, the slope 131. The formula would be: (85 - 72.2) x 113 / 131 = 11.04 The sum of that calculation is called your "handicap differential." This differential is calculated for each round entered (minimum of five, maximum of 20). (Note: The number 113 is a constant and represents the slope rating of a golf course of average difficulty.) Step 2: Determine How Many Differentials To Use Not every differential that results from Step 1 will be used in the next step. If only five rounds are entered, only the lowest of your five differentials will be used in the following step. If 20 rounds are entered, only the 10 lowest differentials are used. Use this chart to determine how many differentials to use in your handicap calculation. Number of Differentials UsedThe number of rounds you are reporting for handicap purposes determines the number of differentials used in the USGA handicap calculation, as follows: Rounds Entered Differentials Used 5-6 rounds Use 1 lowest differential 7-8 rounds Use 2 lowest differentials 9-10 rounds Use 3 lowest differentials 11-12 rounds Use 4 lowest differentials 13-14 rounds Use 5 lowest differentials 15-16 rounds Use 6 lowest differentials 17 rounds Use 7 lowest differentials 18 rounds Use 8 lowest differentials 19 rounds Use 9 lowest differentials 20 rounds Use 10 lowest differentials Step 3: Average Your Differentials Get an average of the differentials used by adding them together and dividing by the number used (i.e., if five differentials are used, add them up and divide by five). Step 4: Arriving At Your Handicap Index And the final step is to take the number that results from Step 3 and multiply the result by 0.96 (96-percent). Drop all the digits after the tenths (do not round off) and the result is handicap index. Or, to combine Steps 3 and 4 into a single formula: (Sum of differentials / number of differentials) x 0.96 Let's give an example using five differentials. Our differentials worked out to (just making up some numbers for this example) 11.04, 12.33, 9.87, 14.66 and 10.59. So we add those up, which produces the number 58.49. Since we used five differentials, we divide that number by five, which produces 11.698. And we multiply that number by 0.96, which equals 11.23, and 11.2 is our handicap index. Thankfully, as we said at the beginning, you don't have to do the math on your own. Your golf club's handicap committee will handle it for you, or the GHIN system if you log in to post scores. Just imagine: Once upon a time, these calculations were all done by hand. Reason to be thankful for computers, right? Handicap Differential in Golf How Golf Handicaps Work: Overview of Their Role and Function What You Need to Know About Golf's World Handicap System If You Want a Golf Handicap, You Need a Certain Number of Scores Course Handicap: What Is It and How Is It Used? How to Convert Your Golf Handicap Index Into Strokes Golf Handicap FAQ Explaining Golf's 'Course Rating' and the USGA Course Rating System Golf Calculators to Estimate Your Handicap What Is the Highest Handicap a Golfer Can Have? USGA Course Rating and Slope Rating Equitable Stroke Control in Golf and Maximum Scores Per Hole Are 9-Hole Golf Scores or Incomplete Rounds OK for Handicap Scores? Are 'Handicap' and 'Handicap Index' the Same? Explanation of Slope Rating in Golf How Do You Use a Handicap in Golf?