WHS differential score calculator
To improve your performance, you need to be able to measure it. Today, tools such as the Kady app or the ffgolf licensed member area allow French golfers to record their daily scorecard. The system then normalises this data according to several criteria in order to calculate an accurate handicap over the season. The differential score is not a mathematical gimmick — it is the most precise indicator for assessing your true level and adjusting your game.
What are the calculation variables of the WHS?
There are 4 variables:
- AGS: your performance (Adjusted Gross Score)
- SSS / Course Rating: professional difficulty of the course
- Slope: course sensitivity for amateur players
- PCC: daily weather/course adjustment
The benefit of calculating the differential score
The difficulty of a course is determined by an actual physical assessment carried out by teams of specialists (often sent by the national federation, such as ffgolf in France).
Official WHS formula (FFGolf)
Differential Score = (113 / Slope) × (Adjusted Gross Score - SSS)
This formula is published and maintained by the Fédération Française de Golf on ffgolf.org. The number 113 is the worldwide standard reference slope. The SSS (Standard Scratch Score) and the Slope are indicated on each course scorecard.
Calculator to determine your performance of the day
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Frequently asked questions
How do I use my adjusted gross score (AGS) to optimise my differential on an unfamiliar course?
Identify the Slope and Course Rating (SSS) before teeing off. If the Slope is significantly above the average of 113, your shots given increase, which mechanically lowers your AGS in the event of a poor performance on a complex hole (via the net double bogey cap). Play with absolute caution on heavily handicapped holes to maximise the effect of this capping on your final differential.
Should I favour back tees to benefit from a better multiplier on my WHS differential?
No. Although back tees (white/blue) offer a higher Course Rating and Slope that theoretically compensate for a heavier gross score, the increased technical difficulty statistically generates real penalties (out of bounds, hazards) greater than the mathematical WHS advantage. Always play the tee corresponding to your drive distance (e.g. less than 200m = forward tees) to maintain a consistency of striking that outweighs the calculation.
What are the strict cases that invalidate the approval of a differential score?
Your differential is categorically rejected by the system if the index portion was not declared numerically before hitting the first golf ball, if the format played is not individual Stroke Play or Stableford, if you have not completed a minimum of 9 consecutive holes, or if the card is not certified on the same day by a licensed marker present for the entirety of the round.
Can the daily adjustment (PCC) save a poor differential achieved in extreme weather conditions?
The Playing Conditions Calculation (PCC) is a statistical adjustment, not a meteorological one. It applies a bonus of -1 to +3 at midnight only if the algorithm detects that the overall field of players has significantly underperformed relative to their expected level. It never saves an individual isolated card — never factor in the hope of a favourable PCC into your risk management strategy in the event of wind or rain.
Why does validating an excellent differential score not always lower my index?
The WHS algorithm is based on a strict rolling window. Your index only decreases if this new differential lowers the average of your 8 best scores from the last 20 recorded. If your 21st exceptional round pushes an even better old card out of the history (your 1st round), your average stagnates or may even increase. Analyse your round history to identify the exact score to be replaced.
Source: Fédération Française de Golf, ffgolf.org. This tool is for guidance only and does not replace the official FFGolf Kady app.
