Estimate your golf handicap index from your score, the course rating, and the slope rating of a round.
The Golf Handicap Calculator computes a score differential for a single round, using the same formula that underlies the USGA/World Handicap System.
A full handicap index is normally the average of your best differentials from your most recent rounds. This tool calculates the differential for one round at a time — enter each round to compare them.
Score Differential = (Score − Course Rating) × 113 ÷ Slope Rating.
A score of 92 on a course with a 71.5 rating and 128 slope gives a differential of about 18.1. Your handicap index is typically the average of your best several differentials.
Modern handicap systems (like the World Handicap System) average your best recent score differentials, which factor in your score, the course rating, and slope rating.
It's a standardized number representing how well you played relative to the course's difficulty, calculated as (score − course rating) × 113 ÷ slope rating.
Averaging recent rounds (typically your best 8 of your last 20) smooths out one-off great or bad rounds, giving a more consistent measure of typical skill level.