Two questions, one page. What is my handicap, and how many strokes do I get on Saturday? The first takes your recent scores and the tees you played them from. The second takes that Index and the slope, rating and par of the tees you are about to play. Everything runs in your browser and nothing you type leaves it.
The calculator
1. Handicap Index from your scores
Enter up to 20 rounds, most recent first. Each round becomes a score differential; your Index is the average of the best ones, per the World Handicap System table below.
The table the calculator uses (Rules of Handicapping, Rule 5.2a)
Score differential = (113 ÷ Slope Rating) × (adjusted gross score − Course Rating − PCC), rounded to one decimal.
| Rounds | Differentials used | Adjustment |
|---|---|---|
| 3 | Lowest 1 | −2.0 |
| 4 | Lowest 1 | −1.0 |
| 5 | Lowest 1 | 0 |
| 6 | Average of lowest 2 | −1.0 |
| 7 or 8 | Average of lowest 2 | 0 |
| 9 to 11 | Average of lowest 3 | 0 |
| 12 to 14 | Average of lowest 4 | 0 |
| 15 or 16 | Average of lowest 5 | 0 |
| 17 or 18 | Average of lowest 6 | 0 |
| 19 | Average of lowest 7 | 0 |
| 20 | Average of lowest 8 | 0 |
2. Course Handicap for the tees you are playing
The formula
Course Handicap = Handicap Index × (Slope Rating ÷ 113) + (Course Rating − Par), rounded to a whole number. Playing Handicap = Course Handicap × the format's allowance.
3. Net double bogey: the most a hole can count
How the calculation works
The World Handicap System, run jointly by the USGA and the R&A since 2020, does three things with a score. It converts it into a score differential, it keeps the best differentials from your most recent twenty rounds, and it turns the resulting Index into strokes for a particular set of tees. The formulas below are the published ones, paraphrased; the calculator above uses them exactly.
Step one: the score differential
A differential asks how you played relative to the difficulty of the course that day. It takes your adjusted gross score, subtracts the Course Rating (what a scratch golfer is expected to shoot from those tees), subtracts any playing conditions adjustment, and scales the result by 113 divided by the Slope Rating. Slope measures how much harder a course plays for a bogey golfer than for a scratch golfer; 113 is the standard, and the range runs from 55 to 155. The differential is rounded to one decimal.
Worked example, from the SCGA's help desk: a 95 on a course rated 73.5 with a slope of 130. Ninety-five minus 73.5 is 21.5. One hundred thirteen divided by 130 is 0.869. Multiply and you get 18.7. Try it in the calculator and you will see the same number in the last column.
Step two: the Handicap Index
With twenty scores on record, the Index is the average of your lowest eight differentials, rounded to a decimal. With fewer than twenty, the table under section one of the calculator applies. Three scores: your single lowest differential, minus 2.0. Six: the average of the lowest two, minus 1.0. Nine to eleven: the lowest three, with no adjustment. The count of differentials used climbs to eight at exactly twenty scores. The maximum Index is 54.0.
The Rules also hold a rising Index back. Your Low Handicap Index is the lowest Index you have had in the past 365 days. Once a new calculation would put you more than 3.0 above it, the soft cap counts only half of anything beyond that line; the hard cap stops the Index at 5.0 above the low point no matter what. The optional field in section one applies both if you enter your Low Index. Most online calculators skip this, which is why they sometimes give a higher number than your handicap service does after a rough stretch.
Step three: the Course Handicap
An Index is portable; a Course Handicap is local. Multiply your Index by the Slope Rating over 113, add the Course Rating minus par, and round to a whole number. A 15.4 Index on tees rated 71.9 with a slope of 131 and a par of 72 works out to 15.4 times 1.159, which is 17.85, minus 0.1, for 17.75, rounded to 18. From a set of tees with a slope of 113 and a rating equal to par, the Course Handicap is simply the Index rounded.
The Playing Handicap applies the format's allowance to that number. Appendix C of the Rules recommends 95 percent for individual stroke play, Stableford and par events, 100 percent for singles match play, 85 percent for four-ball stroke play and 90 percent for four-ball match play. The calculator's format menu carries those figures. Committees can set their own; if the sheet at the club says something else, the sheet wins.
Net double bogey
For handicap purposes no hole can count for more than net double bogey: par, plus two, plus the handicap strokes you receive on that hole. Strokes come from the stroke index printed on the scorecard. With a Course Handicap of 18 you get one stroke on every hole; with 20 you get two on the two hardest holes; a plus handicap gives strokes back starting from the easiest. So a nine on a par 4 where you get one stroke is recorded as a seven. Section three does the arithmetic so you can adjust a card before posting it. The by-hand guide walks through a full card if you want to see every step.
What the number means
A Handicap Index is a measure of potential, not average. Because it uses your best eight of twenty, most golfers shoot above their handicap most of the time, and the Rules are designed that way. If you want to know where an Index sits against other golfers, what counts as a good handicap has the distribution, and the handicap, explained covers the ideas underneath the arithmetic. If slope and rating are still fuzzy, course rating and slope is the place to start; it is the part that makes a 90 on one course worth more than a 90 on another.
Limits
This is an estimate built from the public formulas, and it will match your official Index only if you give it the same scores your provider has, with the same PCC values and the same adjustments. Exceptional score reductions, which knock a further one or two strokes off an Index after a round seven or more below it, are not applied here because they depend on the Index at the moment each round was posted. An official Index requires membership in a club or association and a scoring record maintained there. Use the number above to plan; use the official one to play.
Once the strokes are settled, the round comes down to the shot in front of you and the number to the green. That number is the only thing the Yardage app shows.
Frequently asked questions
Is this my official handicap?
No. An official Handicap Index is issued by a golf club or an authorized association through the USGA's GHIN system or its equivalent abroad, from scores you post there. This calculator uses the same published formulas, so with the same scores it should land on the same number, but it has no standing in a competition.
How many scores do I need?
Three eighteen-hole scores for a first Index. With fewer than 20 the calculator applies the Rules of Handicapping table: with three scores it uses your lowest differential minus 2.0, with 20 it averages the lowest eight.
Can I enter nine-hole rounds?
Not directly. Since 2024, handicap services turn a nine-hole score into an eighteen-hole differential by adding an expected score for the missing nine based on your Index, a figure only your provider has. Enter your eighteen-hole rounds here; if you mostly play nine, your posted record is the place to look.
What is PCC?
The playing conditions calculation, a daily adjustment between minus one and plus three that your handicap provider applies when scores at a course were unusually high or low that day. It is zero on a normal day. Leave it at zero unless you know it.
Why does the Course Handicap include the Course Rating minus par?
Because a Course Rating of 74.5 on a par 72 means the course plays two and a half strokes harder than par for a scratch golfer, and you receive those strokes too. The 2020 Rules of Handicapping added the term in the United States and it is now used worldwide.
What do the soft cap and hard cap do?
They slow a rising Index. Once your Index would be more than 3.0 above your lowest Index of the past year, only half of the further rise counts; it cannot go more than 5.0 above that low point at all. Enter your Low Handicap Index in the optional field to apply them.