A golf handicap index is a numerical measure of a golfer's ability relative to par. It allows players of different skill levels to compete fairly against each other. This calculator provides an estimated handicap index based on your recent rounds, using a simplified version of the World Handicap System (WHS) principles.
To calculate your handicap differential for a single round, the formula is:
Differential = (Adjusted Gross Score - Course Rating) * (113 / Slope Rating)
The '113' is the standard slope rating. Your Handicap Index is then derived from the average of your best differentials, often with a slight adjustment factor.
Enter the details for your last 5 rounds below. The calculator will determine your handicap index by taking the average of your best 3 differentials from these 5 rounds.
Round 1
Round 2
Round 3
Round 4
Round 5
Your Estimated Handicap Index:
Understanding Your Golf Handicap
A golf handicap index is a crucial tool for golfers, enabling fair competition regardless of skill level. It represents your potential scoring ability on a course of standard difficulty. The lower your handicap index, the better your golfing ability.
Key Terms Explained:
Gross Score: Your total number of strokes for a round before any adjustments.
Course Rating: An evaluation of the playing difficulty of a course for a scratch golfer (a golfer who can play to par). It's expressed as a number with one decimal place (e.g., 72.3).
Slope Rating: An evaluation of the relative difficulty of a course for a bogey golfer (a golfer who typically scores around 18 over par) compared to a scratch golfer. It ranges from 55 to 155, with 113 being the standard. The higher the slope, the more difficult the course is for a bogey golfer.
Handicap Differential: This is the core component of handicap calculation. It normalizes your score based on the difficulty of the course you played.
Handicap Index: Your overall measure of playing ability, calculated from your best recent differentials. This index is then used to determine your Course Handicap for any specific course you play, which is the number of strokes you receive during a round.
How to Use This Calculator:
Input Gross Scores: Enter your total strokes for each of your last 5 rounds.
Input Course Rating: Find the Course Rating for the tees you played on each course. This is usually found on the scorecard or the course's website.
Input Slope Rating: Similarly, find the Slope Rating for the tees you played on each course.
Calculate: Click the "Calculate Handicap Index" button.
Important Note: This calculator provides an estimate based on a simplified model. For an official World Handicap System (WHS) Handicap Index, you must register with an authorized golf association in your region, which typically requires submitting a minimum number of scores (often 3 to 5) and adhering to specific rules for score posting and adjustments. This tool is excellent for understanding the concept and getting a quick personal estimate.
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function calculateHandicap() {
var differentials = [];
var roundsData = [];
for (var i = 1; i <= 5; i++) {
var grossScore = parseFloat(document.getElementById("grossScore" + i).value);
var courseRating = parseFloat(document.getElementById("courseRating" + i).value);
var slopeRating = parseFloat(document.getElementById("slopeRating" + i).value);
if (isNaN(grossScore) || isNaN(courseRating) || isNaN(slopeRating) || grossScore <= 0 || courseRating <= 0 || slopeRating <= 0) {
document.getElementById("handicapResult").innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
if (slopeRating 155) {
document.getElementById("handicapResult").innerHTML = "Slope Rating must be between 55 and 155.";
return;
}
if (courseRating 80) {
document.getElementById("handicapResult").innerHTML = "Course Rating must be between 60 and 80.";
return;
}
if (grossScore 150) {
document.getElementById("handicapResult").innerHTML = "Gross Score must be between 40 and 150.";
return;
}
roundsData.push({
grossScore: grossScore,
courseRating: courseRating,
slopeRating: slopeRating
});
}
// Calculate differentials for each round
for (var j = 0; j < roundsData.length; j++) {
var differential = (roundsData[j].grossScore – roundsData[j].courseRating) * (113 / roundsData[j].slopeRating);
differentials.push(differential);
}
// Sort differentials in ascending order
differentials.sort(function(a, b) {
return a – b;
});
// Take the best 3 (lowest) differentials
var bestDifferentials = differentials.slice(0, 3);
// Calculate the average of the best differentials
var sumBestDifferentials = 0;
for (var k = 0; k < bestDifferentials.length; k++) {
sumBestDifferentials += bestDifferentials[k];
}
var averageBestDifferentials = sumBestDifferentials / bestDifferentials.length;
// Apply the WHS adjustment factor (0.96)
var handicapIndex = averageBestDifferentials * 0.96;
document.getElementById("handicapResult").innerHTML = handicapIndex.toFixed(1);
}