Golf Handicap Calculator Formula

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

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Formulas Used

Handicap Index (estimate)

handicap_index = round(avg_diff * 0.96 * 10) / 10

Course Handicap

course_handicap = round(avg_diff * 0.96 * slope_rating / 113)

Best Differential

best_diff = round((diff1 < diff2 ? (diff1 < diff3 ? diff1 : diff3) : (diff2 < diff3 ? diff2 : diff3)) * 10) / 10

Variables

VariableDescriptionDefault
score1Score (Round 1)92
score2Score (Round 2)88
score3Score (Round 3)95
course_ratingCourse Rating72
slope_ratingSlope Rating125
diff1Derived value= (score1 - course_rating) * 113 / slope_ratingcalculated
diff2Derived value= (score2 - course_rating) * 113 / slope_ratingcalculated
diff3Derived value= (score3 - course_rating) * 113 / slope_ratingcalculated
avg_diffDerived value= (diff1 + diff2 + diff3) / 3calculated

How It Works

How Golf Handicap Is Calculated

Formula

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

Handicap Index = Average of Best Differentials x 0.96

The official USGA system uses the best 8 of 20 most recent differentials. This simplified calculator uses 3 rounds to give an estimate.

What Slope and Course Rating Mean

  • Course Rating: The expected score for a scratch (0-handicap) golfer. Typically 68-74.
  • Slope Rating: Measures difficulty for bogey golfers relative to scratch golfers. Range is 55-155, with 113 being standard.

    • Worked Example

    Calculate handicap from scores of 92, 88, and 95 on a course rated 72/125.

    score1 = 92score2 = 88score3 = 95course_rating = 72slope_rating = 125
    1. 01Differential 1 = (92 - 72) x 113/125 = 20 x 0.904 = 18.08.
    2. 02Differential 2 = (88 - 72) x 113/125 = 16 x 0.904 = 14.46.
    3. 03Differential 3 = (95 - 72) x 113/125 = 23 x 0.904 = 20.79.
    4. 04Average = (18.08 + 14.46 + 20.79) / 3 = 17.78.
    5. 05Handicap Index = 17.78 x 0.96 = 17.1.

    Frequently Asked Questions

    How many rounds do I need for a handicap?

    The official USGA World Handicap System requires a minimum of 3 acceptable 18-hole scores to establish a handicap. The more rounds you submit (up to 20), the more accurate the index becomes.

    What is a good handicap for a recreational golfer?

    The average male handicap is about 14; the average female handicap is about 27. A single-digit handicap (under 10) is considered quite good. Scratch golfers have a 0 handicap.

    Does my handicap change from course to course?

    Your Handicap Index stays the same, but your Course Handicap changes. Course Handicap = Handicap Index x Slope Rating / 113. A harder course gives you more strokes.

    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.

    Ready to run the numbers?

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