Ghin Handicap Calculator

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GHIN Handicap Index Calculator

Enter your adjusted gross scores, course ratings, and slope ratings for your recent rounds to calculate your estimated World Handicap System (WHS) Handicap Index. This calculator uses the WHS formula to provide an unofficial estimate of your Handicap Index.

Round # Adjusted Gross Score Course Rating Slope Rating
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Understanding Your GHIN Handicap Index

The GHIN (Golf Handicap Information Network) Handicap Index is a numerical measure of a golfer's demonstrated ability relative to the difficulty of the courses played. It's a cornerstone of fair competition in golf, allowing players of different skill levels to compete equitably. Since 2020, GHIN has adopted the World Handicap System (WHS), standardizing handicapping across the globe.

How the World Handicap System (WHS) Works

The WHS aims to provide a consistent and accurate measure of a golfer's ability. Here are the key components:

  • Adjusted Gross Score: This is your raw score adjusted for Equitable Stroke Control (ESC) or Net Double Bogey, which caps the maximum score you can take on any hole based on your Handicap Index. For this calculator, you should input your score after these adjustments.
  • Course Rating: This represents the playing difficulty of a course for a scratch golfer (a golfer with a Handicap Index of 0.0). It's expressed in strokes to one decimal place (e.g., 72.1).
  • Slope Rating: This indicates the relative difficulty of a course for a bogey golfer (a golfer with a Handicap Index of approximately 20-24) compared to a scratch golfer. It ranges from 55 to 155, with 113 being the standard. The higher the Slope Rating, the more difficult the course is for a bogey golfer.
  • Handicap Differential: This is the core calculation for each round. It converts your adjusted gross score into a value that can be compared across different courses. The formula is:
    Handicap Differential = (Adjusted Gross Score - Course Rating) × 113 / Slope Rating
  • Handicap Index Calculation: Your Handicap Index is calculated by taking the average of your 8 best Handicap Differentials from your most recent 20 scores. If you have fewer than 20 scores, a sliding scale is used (e.g., for 5 scores, the best 1 differential is used; for 10 scores, the best 4 are used). The resulting average is truncated to one decimal place.
  • Playing Conditions Calculation (PCC): The WHS also includes a Playing Conditions Calculation (PCC) which adjusts Handicap Differentials to account for abnormal course or weather conditions. This calculator does not include PCC, as it's typically applied automatically by the official GHIN system.

How to Use This Calculator

  1. Gather Your Scores: Collect your Adjusted Gross Scores, Course Ratings, and Slope Ratings for your most recent rounds. You can typically find Course and Slope Ratings on the scorecard or the course's website.
  2. Enter Data: Input the details for each round into the respective fields. You can enter up to 10 rounds in this calculator. For a more accurate official Handicap Index, 20 scores are recommended.
  3. Calculate: Click the "Calculate Handicap Index" button.
  4. View Result: Your estimated Handicap Index will be displayed.

Example Calculation

Let's say a golfer has the following 5 recent rounds:

Round # Adjusted Gross Score Course Rating Slope Rating
1 85 71.0 125
2 82 70.5 120
3 90 72.0 135
4 80 69.8 118
5 88 71.5 128

Calculating the Handicap Differentials:

  • Round 1: (85 – 71.0) × 113 / 125 = 12.66
  • Round 2: (82 – 70.5) × 113 / 120 = 10.83
  • Round 3: (90 – 72.0) × 113 / 135 = 15.07
  • Round 4: (80 – 69.8) × 113 / 118 = 9.77
  • Round 5: (88 – 71.5) × 113 / 128 = 14.57

The differentials are: [12.66, 10.83, 15.07, 9.77, 14.57].

Sorted, they are: [9.77, 10.83, 12.66, 14.57, 15.07].

For 5 scores, the WHS uses the best 1 differential. In this case, it's 9.77.

Truncating to one decimal place, the estimated Handicap Index is 9.7.

function calculateHandicap() { var differentials = []; for (var i = 1; i 0 && !isNaN(courseRating) && courseRating > 0 && !isNaN(slopeRating) && slopeRating > 0) { var differential = (score – courseRating) * 113 / slopeRating; differentials.push(differential); } } var resultDiv = document.getElementById("result"); if (differentials.length < 3) { resultDiv.innerHTML = "Please enter at least 3 valid rounds to calculate a Handicap Index."; return; } // Sort differentials in ascending order differentials.sort(function(a, b) { return a – b; }); var numScores = differentials.length; var numDifferentialsToUse; // Determine how many differentials to use based on the number of valid scores if (numScores >= 3 && numScores = 6 && numScores = 8 && numScores = 10 && numScores = 12 && numScores = 14 && numScores = 16 && numScores = 18) { // WHS uses best 8 of 20, so for 18-20, it's 8. numDifferentialsToUse = 8; } else { resultDiv.innerHTML = "An unexpected error occurred. Please check your inputs."; return; } var sumOfBestDifferentials = 0; for (var j = 0; j < numDifferentialsToUse; j++) { sumOfBestDifferentials += differentials[j]; } var handicapIndex = sumOfBestDifferentials / numDifferentialsToUse; // Truncate to one decimal place handicapIndex = Math.floor(handicapIndex * 10) / 10; resultDiv.innerHTML = "Your Estimated Handicap Index: " + handicapIndex.toFixed(1) + ""; }

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