Handicap Differential in Golf

"Handicap differential" is a factor used in USGA handicaps. It is a term applied to the difference between your score and the course rating, adjusted for slope rating (we'll explain what that means below). The number that results is used in the calculations that determine a USGA handicap index.

Definition

This is the definition of handicap differential written by the United States Golf Association, as it appears in the USGA Handicap Manual:

"A 'Handicap Differential' is the difference between a player's adjusted gross score and the USGA Course Rating of the course on which the score was made, multiplied by 113, then divided by the Slope Rating from the tees played and rounded to the nearest tenth, e.g., 12.8."

Do You Need to Know Your Handicap Differential?

Golfers who do not carry a USGA handicap index don't need to know what a handicap differential is. And guess what: Even golfers who do have USGA handicap indexes don't need to know! Even if you carry a handicap, you'll never have to calculate or know or deal with handicap differentials ... unless, for some masochistic reason, you want to calculate your own handicap by hand, working through all the math.

Otherwise, the keeping and tracking of a golfer's USGA handicap is almost always done for you, in one way or another. You report your scores, a committee (using software) or a website or a program or an app performs the calculations and lets you know your handicap index.

Calculating Handicap Differentials

Here is the short version of the steps involved in the USGA handicap calculation:

1. Get your scores (using adjusted gross scores), plus the course ratings and slope ratings of the courses where you recorded those scores.
2.  Determine the handicap differential for each of those rounds played, plus the number of differentials you are required to use (some of them are thrown out).
3. Average the remaining differentials.
4. Multiply that average by 0.96 and, there you go, your handicap index.

The equation that produces the handicap differentials used in the USGA Handicap Index formula is this:

(Score minus Course Rating) x 113 divided by Slope Rating = Handicap Differential

Let's use some numbers and run through an example. Say you scored an 82 on a golf course with a USGA course rating of 72.5 and a slope rating of 128. Using those numbers, the equation looks like this:

(82 - 72.5) x 113 / 128

The sum that results — in this example, 8.4 — is your handicap differential for that round of golf.

As noted, the handicap formula requires differentials for each round you are reporting (and you must report a minimum of five and up to your 20 most-recent scores to get a USGA handicap index). The next steps are throwing out some of the higher differentials and averaging the rest, before the final step results in a USGA Handicap Index.

In Summary

1. Note again that a "handicap differential" is a factor in calculating a USGA Handicap Index. As part of that process, handicap differentials for each of your rounds are tallied, and the lowest ones (how many depends on the rounds played) are averaged.
2. You don't actually need to know how to calculate handicap differential, what its role is in the handicap formula, or even what it is. Other people, other computer programs do the work for you. Be thankful for that!