Golf Handicap Calculator
World Handicap System index from your last 20 rounds, plus course handicap for today's round.
Add your last rounds (up to 20). Adjusted Gross Score is your score after any net double bogey cap.
Course Handicap for today's round
Course Handicap
How the WHS Handicap Index is calculated
Each round produces a score differential that removes the influence of course difficulty:
differential = (Adjusted Gross Score − Course Rating) × 113 ÷ Slope Rating
Worked example: shoot an 86 on a course with Course Rating 71.5 and Slope Rating 125: (86 − 71.5) × 113 ÷ 125 = 14.5 × 0.904 = 13.1. A harder course (higher slope) shrinks the differential; an easier course (lower slope) inflates it, so rounds from different courses stay comparable.
Once you have at least 3 differentials, your Handicap Index is the average of a set number of your lowest (best) differentials from your most recent 20 rounds — more of your rounds count as you accumulate history, per the official WHS table (3 rounds uses your best 1 minus a 2.0 adjustment; 20 rounds uses the best 8, no adjustment). The result is truncated — not rounded — to one decimal place, and capped at 54.0.
Course Handicap
Handicap Index measures general ability; Course Handicap translates it to strokes for the specific tees you're playing:
Course Handicap = Index × (Slope ÷ 113) + (Course Rating − Par)
For a 12.3 Index on a course with Slope 125, Course Rating 71.5 and Par 72: 12.3 × (125 ÷ 113) + (71.5 − 72) = 13.6 − 0.5 = 13 strokes, rounded to the nearest whole number. That's how many strokes you subtract from your gross score to get your net score for that round.
Practical tip: only your best differentials count, so a few bad rounds won't inflate your index — but you still need honest, complete scores from every round (including bad ones) for the system to work, since sandbagging by not posting bad rounds is easy to spot and against the rules.
Golf Handicap Calculator: frequently asked questions
How is a WHS Handicap Index calculated?
Each round gives a score differential: (Adjusted Gross Score − Course Rating) × 113 ÷ Slope Rating. Your Handicap Index is the average of your best differentials from up to your last 20 rounds, based on a lookup table (e.g. best 8 of 20), truncated to one decimal.
What is the difference between Handicap Index and Course Handicap?
Handicap Index is a portable number that reflects your general ability, calculated from your scoring history. Course Handicap adjusts that index for the specific course and tees you are about to play, using that course's Slope Rating, Course Rating and par.
How many rounds do I need for a Handicap Index?
You need at least 3 scores to get an initial Handicap Index. Accuracy improves as you add more rounds, and the calculation uses up to your most recent 20.
What are Course Rating and Slope Rating?
Course Rating is the expected score for a scratch (0 handicap) golfer, usually close to par. Slope Rating measures relative difficulty for a bogey golfer versus a scratch golfer, ranging from 55 to 155 with 113 as the neutral average.
Why is my Handicap Index capped at 54.0?
The World Handicap System sets 54.0 as the maximum Handicap Index for any player, regardless of how high your calculated average differential is, so the sport stays accessible to beginners.