Post every round you play under the Rules of Golf, at home or away, and let the system sort it out. That is the short answer. The single most useful takeaway: your handicap is built from your eight best score differentials out of your most recent twenty, so one ugly number on a Saturday card will not wreck you. It just sits in the pile until it ages out.
I get this question a lot from playing partners, usually right after someone signs for a 94 and asks whether it "has to go in." Yes, it goes in. Here is how the rest of it works.
What Counts as a Postable Score
You post a score when you play a round of at least 9 holes on a rated course, alone or with others, in a format where you're playing your own ball. That covers stroke play, match play, Stableford, and most casual weekend games. Four-ball and scramble formats do not get posted as individual scores, though your own ball score in some team formats can be.
Two things trip people up. First, you post adjusted gross score, not your raw score. There is a cap on how high any single hole can count, currently net double bogey. If you make a 9 on a par 4 where you get one stroke, the hole counts as a 7 for posting. Second, you post even on days you feel terrible. There is no "I was tired" exemption.
You also need to post away rounds. If you shoot 88 at a course you have never seen, with a slope rating of 132 and a course rating of 71.4, that score goes in your record just like a home round. The math handles the difficulty difference for you.
How the Math Turns Scores Into an Index
Every posted score becomes a score differential. The formula is (adjusted gross score minus course rating) times 113, divided by slope rating. That 113 is the standard slope, the baseline the system normalizes everything against.
Say you shoot 88 from a tee rated 71.4 with a slope of 132. Subtract 71.4 from 88 and you get 16.6. Multiply by 113 to get 1875.8. Divide by 132 and your differential is 14.2. Same 88 at a course rated 69.8 with slope 118 gives you 17.4. Harder course, lower differential. That is the point.
Now the index itself. The system takes your most recent 20 differentials, picks the 8 lowest, averages them, and multiplies by 0.96. Suppose your eight best are 12.1, 13.4, 14.2, 15.0, 15.6, 16.3, 17.0, and 17.8. That averages to 15.18. Times 0.96 gives 14.57, which rounds to a handicap index of 14.6.
With fewer than 20 scores, you use a smaller subset. Five scores means your lowest one. Nine scores means your lowest three. Fifteen scores means your lowest six. The full 8-of-20 kicks in only once you have twenty posted rounds. If you want to see how your own numbers shake out, our free golf handicap calculator at fairwayvip.com/calculator runs the whole thing in a few seconds.
Turning Your Index Into a Course Handicap
Your index is not the number of strokes you get on a given day. Course handicap equals index times slope rating divided by 113, plus course rating minus par. If your index is 14.6 and you play a course with slope 132 and par 72, you get 14.6 times 132 divided by 113, which is 17.1, then adjusted by the rating-minus-par term. On a slope 113 course, your course handicap is basically your index.
This is why the same player can get 15 strokes at one club and 19 at another. Nothing changed about your ability. The course did.
One more habit worth building. Post the same day you play, before the details blur. You can use the handicap index calculator at