Golf Handicap Calculator
Score differentials, your World Handicap System Index, and USGA scramble allowances, from the rounds you type in. Everything runs in your browser and nothing is uploaded.
How to use
- Add a row for each of your most recent rounds, oldest first, and type the adjusted gross score, the course rating, and the slope rating. The Index updates as you type.
- For a 9-hole round, switch the Holes selector to 9 and enter the 9-hole rating and slope printed on the scorecard. Add your current Handicap Index so the round can be converted.
- Read your Handicap Index under the rows, with the differentials that entered the average marked Counted.
- For a scramble, pick the team size and enter each player's Course Handicap to see the recommended playing handicap per player. Enter a plus handicap as a negative number.
What a differential is
Every round you post becomes one number, the Score Differential. It takes your adjusted gross score, which is your gross score with penalty strokes and any hole capped at your net double bogey, and rescales it against the course you played: (113 / slope rating) × (adjusted gross score - course rating).
The slope in that fraction is what makes differentials comparable between courses. A hard course pushes the same score to a higher differential than an easy one, and lower is always better.
Your Handicap Index comes from the lowest 8 differentials of your last 20 rounds, not the average of all of them. The rules measure what you are capable of when you play well. One bad day barely moves your Index, and a genuinely better game shows up within a few rounds.
Worked examples
An 18-hole round: you shoot 95 on a course with a 73.2 rating and a 128 slope. The differential is (113 / 128) × (95 - 73.2) = 19.2.
A 9-hole round, from the USGA's own example: a player with a 14.0 Index posts a 41 over 9 holes with a 33.8 rating and a 113 slope. The 9-hole differential is 7.2, the expected differential for a 14.0 player is 8.5, and the round enters the record as an 18-hole differential of 15.7.
A full record: if the lowest 8 of your last 20 differentials average 16.4, your Handicap Index is 16.4. Under the pre-2024 rules the same record produced 15.7, because the average was multiplied by 0.96.
A two-person scramble with Course Handicaps of 10 and 20: the low player gets 35% of 10, which rounds to 4 strokes, and the high player gets 15% of 20, which is 3. You play the round with playing handicaps of 4 and 3.
Method and sources
The math follows the USGA Rules of Handicapping, effective January 2024. Every constant was checked against the published rules text at usga.org.
- Score Differential, Rule 5.1a: (113 / slope rating) × (adjusted gross score - course rating), rounded to the nearest tenth with .5 up. Minus differentials round upward towards zero, Rule 5.1c. The Playing Conditions Calculation is omitted; it ranges from -1.0 to +3.0 and needs the day's field scores, Rule 5.6.
- Handicap Index, Rules 5.2a and 5.2b: the average of the lowest 8 of the most recent 20 differentials, rounded to the nearest tenth, capped at 54.0 by Rule 5.3. Records of 3 to 19 differentials use the published table, reproduced here as data: 3 scores take the lowest 1 with a -2.0 adjustment, 4 scores the lowest 1 with -1.0, 6 scores the lowest 2 with -1.0, then the lowest 2, 3, 4, 5, 6, 7, and 8 as the record grows. The 0.96 bonus for excellence was removed in the 2024 revision.
- Nine-hole rounds, Rule 5.1b: the unrounded 9-hole differential is combined with the expected differential for 9 holes based on your current Handicap Index, then rounded once. The USGA publishes the method and worked examples: a 14.0 Index player's expected differential is 8.5 and a 15.0 player's is 9.0. For the values in between, this tool uses the 0.52 × Index + 1.2 formula that handicap software implements, which reproduces both published examples.
- Scramble allowances, Appendix C: 35% low and 15% high for two players, 30/20/10 for three, and 25/20/15/10 for four, applied to Course Handicaps lowest first and rounded to whole strokes.
This page is an estimate for information only. Caps, Low Handicap Index tracking, exceptional score reductions, and same-day playing condition adjustments are not modeled. Your official Handicap Index comes from your golf club through the World Handicap System.
Frequently asked questions
Do you store my scores or send them anywhere?
No. The calculator runs entirely in your browser tab. Your scores never leave your device, nothing is saved on our side, and the page sets no cookies. Ad slots on the page are served by third-party networks with their own privacy policies, and they never receive what you type.
What are course rating and slope rating?
The course rating is the score a scratch golfer, a 0.0 Index, is expected to post on a set of tees. The slope rating says how much faster the course gets harder for a bogey golfer than for a scratch one, and 113 is the neutral value. Both are printed on the scorecard, every set of tees has its own pair, and 9-hole courses carry 9-hole ratings.
How do 9-hole rounds count toward my Index?
Since January 2024 they count right away. The WHS computes a 9-hole Score Differential from the 9-hole rating and slope, then adds an expected differential for the 9 holes you did not play. That expected value depends only on your current Handicap Index: a 14.0 Index player adds 8.5. This calculator does the same conversion when you enter your current Index alongside the round.
Why doesn't this calculator apply the 0.96 multiplier?
Because the USGA removed it. From 2020 to 2023 the Index was the average of the lowest 8 differentials multiplied by 0.96, a bonus for excellence. The 2024 revision of the Rules of Handicapping dropped the multiplier, so today's Index is the plain average rounded to the nearest tenth. Calculators that still multiply by 0.96 follow the old rules and read about 4 percent lower.
What is a scramble allowance?
A scramble is a team format where everyone plays from the team's best shot. The USGA's Appendix C recommends that each player use only part of their Course Handicap: 35% for the low player and 15% for the high player on a two-person team, 30/20/10 for three players, and 25/20/15/10 for four. The biggest share goes to the lowest handicap. A committee can adjust these percentages for a specific event.
Why does my result differ from my GHIN app?
A few reasons. GHIN applies a Playing Conditions Calculation, a same-day adjustment between -1.0 and +3.0 that needs every score posted at your course that day, so a browser tool cannot compute it. It also applies cap limits against your Low Handicap Index, reductions for exceptional scores, and allowances based on unrounded Course Handicaps. This calculator leaves those out on purpose, so treat the result as a close estimate rather than an official Index.