Your rounds
3 rows · 0 complete1. Score differential
Each round becomes a differential: (113 ÷ Slope) × (Score − Course Rating). Course rating and slope are printed on the scorecard for the tees you played. If you cannot find them, the USGA course rating database lists them.
2. Best rounds only
The World Handicap System averages your lowest differentials — 1 of 3, 2 of 6, 8 of 20 — and applies an adjustment at small sample sizes. Rounds counted toward your index are marked in gold.
3. Nine-hole rounds
A 9-hole differential is doubled to make an 18-hole equivalent. The official system instead combines nine-hole scores using an expected score based on your current index, which this calculator does not track.
This calculator follows the USGA’s published Rules of Handicapping (Rule 5.2a) for the number of differentials used and the adjustment applied at fewer than 20 rounds. It gives a close estimate: an official Handicap Index has to come from an authorised golf association, not from a free handicap calculator.
