GameCalc

Golf Handicap Calculator

One round, one quick handicap estimate.

Score

Course Rating

Slope Rating

Handicap Index

12.5

Differential: 13

What you entered

Score: 85Course Rating: 72Slope Rating: 113

1
Adjusted gross score minus course rating
85 - 72= 13
2
Handicap differential
(85 - 72) x 113 / 113= 13
3
Handicap index (single-round simplified)
13 x 0.96= 12.48

Result

Handicap Index: 12.5

Handicap differential by score, course rating, and slope

The differential is the score minus the course rating, scaled by 113 over the slope rating. 113 is the slope of a course of average difficulty.

Score	Course rating	Slope	Differential	Handicap index
78	73.2	135	4.0	3.9
82	72.4	118	9.2	8.8
85	72.0	130	11.3	10.8
85	72.0	113	13.0	12.5
95	71.5	125	21.2	20.4
100	70.0	113	30.0	28.8

The same 85 gives a differential of 13.0 on an average course but only 11.3 on a harder one, which is exactly what slope is for. This is a single-round estimate; a real handicap index averages your best 8 differentials from the last 20 rounds.

Differential = adjusted score vs. course difficulty

A handicap differential takes your score, subtracts the course rating (how hard the course plays for a scratch golfer), and adjusts for slope (the difficulty gap between a scratch and bogey golfer) — this standardizes scores across different courses.

Why the official index uses multiple rounds

The USGA Handicap Index uses the best 8 of your most recent 20 differentials, then multiplies by 0.96 — a single-round estimate is a rough approximation, but gives you a starting point before you build up a full history.

Frequently asked questions

I shot 92 on a course rated 72.1 with slope 131 — what's my handicap differential?

Your differential is (92 − 72.1) × 113 ÷ 131 = 17.2. You'd need at least 3 rounds to get an initial index, but this single differential gives you a starting estimate.

How is a golf handicap different from a bowling handicap?

Golf handicaps are index-based, adjusting for course difficulty via slope and rating so your handicap travels across courses. Bowling handicaps are simpler — a fixed percentage of the gap between your average and a target score, recalculated weekly.

What does the slope rating mean?

Slope ranges from 55 to 155 (113 is standard) and measures how much harder a course plays for a bogey golfer compared to a scratch golfer. A slope of 150 means high-handicappers will struggle much more than low-handicappers on that course.