How to use the Golf Handicap Calculator
- Enter your recent 18-hole scores, most recent first, separated by commas.
- Enter the course rating and slope rating from the scorecard for the tees you played.
- The calculator selects how many differentials to average based on how many scores you entered.
- Read your handicap index — the portable number — and the course handicap for the tees entered.
- Add scores as you play; twenty rounds gives the full-strength calculation.
How the calculation works
Every round becomes a score differential: (score − course rating) × 113 ÷ slope rating. Course rating is the expected score for a scratch golfer, so the subtraction measures how far above scratch you played. Dividing by slope and multiplying by 113 — the slope of a course of average difficulty — normalises the result so a 90 on a brutal course and an 84 on an easy one can be compared directly.
The World Handicap System, in force since 2020, averages the best 8 of your most recent 20 differentials. Averaging the best rather than all of them makes the index a measure of demonstrated potential, not typical play, which is why golfers shoot their handicap far less often than they expect — roughly one round in five. With fewer than twenty scores, a published table sets how many to count, from the single best of three up to the best eight of twenty; this calculator applies that table.
The index is then converted for the tee you play: course handicap = index × slope ÷ 113 + (course rating − par). The final term is what makes a 6,900-yard championship tee give more strokes than the forward tee on the same course. Note this calculator omits the WHS soft cap, hard cap and playing-conditions adjustment, all of which need a full scoring record held by a handicapping body.
Differential = (score − course rating) × 113 ÷ slope; Index = average of best 8 of 20 × 0.96; Course handicap = index × slope ÷ 113 + (rating − par)Source: USGA and R&A, Rules of Handicapping: World Handicap System (2024 revision), Rules 5 and 6.
Worked example
Eight scores on a course rated 71.2 with a slope of 128, the best being 85.
- Differential for the 85 = (85 − 71.2) × 113 ÷ 128 = 12.2.
- With eight scores, the table counts the best two.
- If the best two differentials are 12.2 and 13.1, the average is 12.65.
- Index = 12.65 × 0.96 = 12.1.
A handicap index of about 12.1, which plays as a 13 course handicap off those tees.
Frequently asked questions
What is the difference between index and course handicap?+
The index is portable and course-independent. The course handicap converts it to strokes for the specific tees you are playing.
Why average only the best eight?+
WHS defines a handicap as demonstrated potential ability, not average performance, so it looks at your better rounds.
Do I need twenty scores?+
No. The table handles as few as three, though the index is provisional and moves sharply until you have a fuller record.
Is this an official handicap?+
No. Official indexes must be issued by an authorised handicapping body from verified scores with net double bogey adjustment applied.
Last reviewed September 1, 2026. We review this page whenever the underlying formula, tax year, published rate or standard changes.