Golf Handicap Calculator
Estimate your golf handicap index from your course rating, slope rating and recent round scores.
Your score differential per round, in the order you played them — the handicap index uses only your best 3 of these 6, not a straight average of every round.
A simplified estimate using your best-half differentials — the official USGA formula uses more detailed round-count tables.
About the Golf Handicap Calculator
This calculator estimates a golf handicap index from a course rating, slope rating and a list of your recent round scores — a simplified version of the differential-based system golfers use to compare skill across different courses of varying difficulty.
Golfers use it after a round to track how their handicap is trending, before a tournament to submit or verify an estimated index, or just to satisfy curiosity about where a handful of recent scores puts them without digging through an official handicap tracking app.
Enter your course and slope rating along with a comma-separated list of recent scores, and it calculates a score differential for each round before combining the best ones into an index.
How it’s calculated
Each round produces a score differential: (your score − course rating) × 113 ÷ slope rating. The 113 constant is the slope rating of a course of "standard" difficulty, which normalizes differentials so rounds on harder or easier courses can be fairly compared against each other.
The handicap index is calculated from only your best half of recent differentials (not all of them), averaged and then multiplied by 0.96 — a deliberate downward adjustment baked into the handicap system. This calculator uses that same best-half approach as a simplified stand-in for the official USGA method, which uses more detailed round-count tables depending on how many rounds you've played.
Frequently asked questions
Why does the handicap only use my best rounds instead of all of them?
The handicap system is meant to reflect potential skill level, not average performance, so it deliberately weights toward your better rounds rather than averaging in every score — using only the best half of recent differentials is a simplified version of that same idea.
What are course rating and slope rating?
Course rating is the expected score for a scratch (zero-handicap) golfer on that course, while slope rating measures how much harder the course plays for a bogey golfer relative to a scratch golfer — both numbers are printed on the scorecard or the course's official rating sheet.
How many rounds do I need for an accurate handicap?
More recent rounds generally produce a more stable and representative handicap. The official USGA system uses a sliding scale based on how many of your last 20 rounds are available; this calculator's simplified best-half method works reasonably with as few as a handful of rounds, but stabilizes further with more.
Is this the same number as my official USGA Handicap Index?
It's a close approximation using the same core differential formula, but the official USGA system applies more detailed round-count tables and additional adjustments that this simplified calculator doesn't replicate exactly — treat this as a solid estimate, not an official index.
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