Golf Handicap Differential Calculator Formula

Understand the math behind the golf handicap differential calculator. Each variable explained with a worked example.

Formulas Used

Handicap Differential

differential = (adjusted_score - course_rating) * 113 / slope_rating

Strokes Over Course Rating

over_par = adjusted_score - course_rating

Variables

VariableDescriptionDefault
adjusted_scoreAdjusted Gross Score88
course_ratingCourse Rating72.1
slope_ratingSlope Rating131

How It Works

Golf Handicap Differential

The handicap differential normalizes scores across courses of different difficulty using the USGA/WHS formula.

Formula

Differential = (Adjusted Score - Course Rating) x 113 / Slope Rating

113 is the standard slope rating. A course with slope 131 is harder than standard, so the formula adjusts the differential downward. Your handicap index is the average of your best differentials (best 8 of last 20 rounds).

Worked Example

Score of 88 on a course rated 72.1 with slope 131.

adjusted_score = 88course_rating = 72.1slope_rating = 131
  1. 01Over rating = 88 - 72.1 = 15.9
  2. 02Differential = 15.9 x 113 / 131 = 13.7

Frequently Asked Questions

What is a good handicap?

Average male golfer: 14-16. Average female: 28-30. Single digit (below 10) is well above average. Scratch golfer is 0, and plus handicaps are below par players.

What is slope rating?

Slope rating (55-155) measures course difficulty for bogey golfers relative to scratch golfers. Higher slope means the course is disproportionately harder for higher-handicap players.

How many rounds do I need?

Under the World Handicap System, you need at least 54 holes (3 rounds of 18) to establish a handicap index.

Learn More

Guide

Golf Handicap Guide - How the Handicap Index System Works

Learn how the golf handicap index is calculated under the World Handicap System. Covers handicap differentials, course rating, slope rating, and playing handicap.