Golf Course Rating Calculator

This calculator applies the official USGA handicap differential formula — (your score minus the course rating) times 113, divided by the course's slope rating — where 113 is the USGA's fixed reference slope for an "average difficulty" course, defined as part of the Score Differential formula the USGA and the R&A jointly publish under the World Handicap System, so a differential expresses how many strokes above (or below) course-adjusted par you played, normalized for course difficulty. A true USGA Handicap Index averages your best 8 of your last 20 differentials rather than a single round's differential; since this tool takes a single average-score input instead of a full scoring history, it approximates that "best rounds tend to beat your average" effect with a reduction factor that scales with how many rounds you specify (roughly 85% of the raw differential for just a few rounds, rising toward 93% as you factor in more rounds) — this is a deliberate simplification, not the real USGA algorithm, so don't expect it to match your official index exactly. From the estimated index it derives your course handicap (index scaled by that course's slope, adjusted for how the course rating compares to a standard par of 72) and a target score for that specific course and tee.

Net score subtracts the course handicap from your gross average to show roughly how you'd compare to scratch after adjustment. Treat the handicap index here as a ballpark estimate for planning purposes — for anything official (tournament eligibility, handicap-based betting, league play), only a real USGA-issued index calculated from your actual round-by-round scoring history counts.