Under the World Handicap System, your Handicap Index is the average of your lowest 8 score differentials from your last 20 rounds. Each differential is (113 ÷ Slope) × (adjusted score − Course Rating). Shooting 85 on a course rated 70.5 with a slope of 125 gives (113 ÷ 125) × 14.5 = 13.1.
Club golfers who keep their own records, or want to check what their club app shows, need three numbers from the World Handicap System: the differential for each round, the Handicap Index built from those differentials, and the Course Handicap for the tees they are about to play. This calculator does all three. Paste your differentials and it applies the WHS table for 3 to 20 rounds, including the -2.0 and -1.0 adjustments for short records, and lists which rounds counted. Switch modes to turn one score into a differential or an index into strokes received. It does not apply the soft and hard caps against your low index, exceptional score reductions or net double bogey hole limits, so an official index from your association can differ.
Choose Handicap Index, Score differential or Course Handicap; only the fields that mode needs are shown.
Paste 3 to 20 differentials separated by commas, spaces or new lines, oldest first; more than 20 keeps the latest 20.
Course Rating and Slope Rating are printed on the scorecard for each set of tees; add your adjusted score and PCC, or your index and par.
The steps show each part of the formula, and the table ranks your differentials and marks the ones averaged.
Result Result: 13.1
Strokes over Course Rating: 14.5
Slope factor (113 ÷ Slope): 0.904
Fourteen and a half strokes over the rating on a slightly harder-than-standard course gives a differential of 13.1.
Result Result: 14
Strokes over Course Rating: -0.5
Course Handicap before rounding: 13.55
The slope adds about 1.6 strokes and the rating half a stroke under par takes 0.5 off, so the player receives 14 strokes.
Result Result: 4.5
Differentials used from: 20
Lowest differentials averaged: 8
WHS adjustment: 0
Average of counted differentials: 4.5
With 20 differentials the WHS averages the best 8; here 1 to 8 average 4.5.
Differential = (113 ÷ Slope) × (AGS − CR − PCC); Index = mean of lowest N differentials + adjustment; Course Handicap = Index × Slope ÷ 113 + (CR − Par)
AGSCRSlopePCCNA differential rescales strokes over the Course Rating to a course of standard difficulty, slope 113, and is rounded to one decimal. The index takes the lowest N of your most recent 20 differentials, from 1 of 3 up to 8 of 20, with -2.0 for three rounds and -1.0 for four or six. The Course Handicap converts the index back to the tees in play and is rounded to a whole number.
The WHS lets you get an index after 54 holes, which is three 18-hole rounds or the nine-hole equivalent. With three differentials the lowest one counts and 2.0 is taken off it, so a new player's index starts slightly low until more scores arrive.
The index is meant to show what you can shoot on a good day, not your average. Averaging the lowest 8 of your latest 20 differentials gives a figure close to your potential while still moving as your form changes round by round.
113 is the slope of a course of standard relative difficulty. A slope above 113 means the course plays harder for a bogey golfer than for a scratch golfer, so higher handicaps receive more strokes there; below 113 they receive fewer.
The playing conditions calculation adjusts differentials when scores on a day were well above or below normal because of weather or course set-up. It ranges from -1 to +3 and is set by the handicap software after play, so use 0 unless your record shows otherwise.
Your index assumes a course of slope 113 rated at par. The Course Handicap scales it by the slope of the tees you play and adds the gap between Course Rating and par. An index of 12.4 from 128-slope tees rated 71.5 on a par 72 becomes 14 strokes.
A plus index is better than scratch and is written as a negative number in calculations. Enter +1.5 as -1.5 and a differential below the Course Rating, such as 68 on a 70.2 course, comes out negative automatically.
Using this tool in an assignment, article or report? Copy a citation, or a link for your website.
Tools Directory Editorial Team. (2026, October 10). Golf Handicap Calculator. Tools Directory. Retrieved October 26, 2026, from https://tools.milunir.com/sports/golf-bowling-and-racquet-sports/golf-handicap-calculator/
Tools Directory Editorial Team. “Golf Handicap Calculator.” Tools Directory, 10 Oct. 2026, https://tools.milunir.com/sports/golf-bowling-and-racquet-sports/golf-handicap-calculator/. Accessed 26 Oct. 2026.
Tools Directory Editorial Team. “Golf Handicap Calculator.” Tools Directory. Last modified October 10, 2026. Accessed October 26, 2026. https://tools.milunir.com/sports/golf-bowling-and-racquet-sports/golf-handicap-calculator/.
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