Three numbers that get called "handicap"

People use one word for three different things, which is where most of the confusion comes from.

• Handicap Index is your portable number, to one decimal place, like 15.3. It describes your ability on a course of standard difficulty and it travels with you to any course in the world.
• Course Handicap is the Index converted into whole strokes for the specific tees you're playing today. A 15.3 might be a 17 from the back tees at a hard course and a 13 from the forward tees at an easy one.
• Playing Handicap is the Course Handicap after any allowance for the format, like 95% in a stroke-play competition. Most casual games skip this step.

When someone says "I'm a 15," they mean their Index.

How the Index is calculated

Every round you post gets turned into a score differential, which answers the question "how well did you play, given how hard the course was?" The formula is:

Course Rating is what a scratch golfer should shoot from those tees, something like 71.2. Slope Rating is how much harder the course gets for a bogey golfer than for scratch, from 55 to 155, with 113 as the average. PCC is a small adjustment for unusually hard or easy weather on the day, usually zero.

Your Index is the average of your best 8 differentials from your most recent 20 rounds. Not your average round. Your good ones. That's deliberate: a handicap is meant to measure what you're capable of, so that in a competition it's hard to win just by having a lucky day. It also means your Index is usually two or three strokes lower than your typical score over par, and that's normal. A 15 shooting 90 hasn't had a bad day. They've had an average one.

With fewer than 20 rounds posted, the system uses fewer of your best scores and knocks a stroke or two off as a safety margin. With exactly three rounds, it takes your single best differential minus two.

The cap on bad holes

Before a round is posted, every hole is capped at net double bogey: double bogey plus however many handicap strokes you get on that hole. So if you're a 15 and you get a stroke on a par 4, the most that hole can count for handicap purposes is a 7, even if you wrote down a 10. Your actual score in the competition is still the 10. This cap is why one disastrous hole doesn't wreck your Index, and why your handicap scores and your real scores are sometimes a stroke or two apart.

How to get one

You need to belong to a golf club or an association that's authorized to issue handicaps, and you need to post 54 holes of scores. Those can be any mix of 18- and 9-hole rounds, and your first Index appears the day after you post the last of them.

In the US, the system is called GHIN and it's run by the USGA through state and regional golf associations. You don't need to join a private club. Most state associations offer an online membership, often under $50 a year, that gets you a GHIN number and the app. Public courses and driving ranges sometimes run their own clubs that do the same thing. Search for your state golf association and "join."

Elsewhere, your national golf union handles it: England Golf, Golf Australia, Golf Canada, and so on. The system underneath is the same World Handicap System, so an Index from one country works in another.

Rounds you post have to be played on a rated course under the rules, with at least one other person present. A round played alone doesn't count in the US. The range doesn't count. Nine holes count. Post everything, good and bad, usually on your phone before you leave the parking lot.

Converting it to strokes on the day

Say your Index is 15.0 and you're playing tees with a Slope of 128, a Course Rating of 71.2 and a par of 72. That's 15.0 × 1.133, which is 17.0, plus 71.2 minus 72, which is −0.8. Total 16.2, so you get 16 strokes. Most clubs post a conversion chart by the first tee, and the GHIN app does it when you type in the course.

The strokes are given out by the stroke index on the scorecard. With 16, you get one stroke on the sixteen hardest holes and none on the two easiest. With 20, you get one on every hole and a second one on the two hardest.

What's a good handicap?

The USGA's 2025 figures put the average Index at 14.2 for men and 28.8 for women, among the roughly 3.7 million Americans who keep one. Bear in mind that's the average of people who care enough to keep a handicap. The average of everyone who plays is higher.

Single digits means you're a good club golfer. Scratch, meaning 0.0, means you shoot about par and you're in the top couple of percent. A "plus" handicap, like +2.0, means you're better than scratch and you give strokes back to the course. The maximum Index is 54.0 for everyone, which is roughly triple bogey on every hole, and it exists so a complete beginner can play in the club's net competitions from day one.

Using it in a game

In match play between two players, the lower handicap plays off scratch and the higher one gets the full difference in Course Handicaps, taken on the hardest holes. In a stroke-play competition, each player's Course Handicap is usually cut to 95% before being subtracted, which slightly favors the lower handicaps and reflects the fact that the field is bigger. In a casual Saturday game, nobody bothers with the 95% and most groups just use the difference.

Net scoring, Stableford and the other formats this feeds into are in golf scoring explained.

Questions

How often does it change?

Every time you post a score. The update runs overnight, so your new Index is there the next morning.

Can I have a handicap without joining a club?

Yes, through a state or regional golf association's online membership in the US, or through your national union's equivalent elsewhere. They're inexpensive and that's what they're for.

Do I have to post bad rounds?

Yes, and good ones. Posting only the bad ones makes you a sandbagger and posting only the good ones gives you a vanity handicap. Either way it stops working. Clubs can and do add penalty scores to the records of players who leave rounds out.

Does a round from the forward tees count?

Yes, as long as the tees are rated, and nearly all are. The Course Rating and Slope for those tees are what the calculation uses, so moving up doesn't inflate your Index.

My handicap went up after a decent round. Why?

Because a round from 20 rounds ago that was one of your best 8 just dropped off the end of the list. It happens to everyone and it's the system working, not a mistake.

Where's the official text?

The USGA's handicapping pages have the Rules of Handicapping, a course handicap calculator and the GHIN sign-up.

The number tells you the trend, not the cause

A handicap moving from 18 to 15 over a summer tells you something's working. It doesn't tell you what. For that, I film my range sessions and keep the clips by date, which lets me put a swing from June next to one from September and see what changed. Setting that up takes a minute: how to film your golf swing with an iPhone. Impact Reel keeps each session in its own library and album on the phone, with notes, so the comparison is a couple of taps.