World Handicap System,
Fair Matches on Any Tee.
Free golf calculators: handicap index from score differentials, course handicap conversion, and the game-improvement math that lowers scores.
Score Differential Formula
(Score - Course Rating) × 113 ÷ Slope Rating: the international USGA baseline.
Best 8 of 20 Rounds
Computes potential scoring ability by averaging the lowest 8 differentials of your last 20 rounds.
Course Handicap Conversion
Converts index into playing strokes based on specific tee box difficulty.
GolfMath Tools
Score Differential Calculator
Score differential from a round — adjusted gross score against course rating and slope.
Course Handicap Calculator
Index to course handicap — your strokes for today's tee, with the playing-condition adjustment.
Game Improvement Calculator
Where the strokes hide — putt counts, penalties, and up-downs scored against your index expectations.
Expected Score Calculator
The score your index predicts on any course — best-round potential vs average-day reality.
Practical Guides & Best Practices
The World Handicap System, explained in one page
Differentials, slope, the best-8-of-20 average, and why the modern index is fairer than ever.
The strokes are in the short game: the data behind faster improvement
What stroke-gain research says about where scores drop fastest, by handicap level.
12 mistakes people make with golf scoring
The recurring errors we see in golf scoring — what causes each one, and the habit that prevents it.