The idea in one paragraph
Golfers differ by tens of strokes a round, so a game between them would be decided before the first tee without a way to even it out. A handicap measures how many strokes better or worse than the course expects you usually play. In a group game those strokes are handed out on particular holes, so the contest on every hole is between net scores rather than raw ones. Everything below is the machinery that turns one number into those strokes.
Step 1: the Handicap Index
Your Handicap Index is the official figure from a handicap authority, built from the best of your most recent scores and adjusted for how hard each course was on the day. It travels with you and is not tied to any one course. It is a number like 10.4, and it can be negative for a golfer better than scratch, which is written as a plus handicap such as +2.1.
In a group game you take it exactly as it is. A good scorekeeper never rounds it, trims it or adjusts it toward the best player in the group, because the whole point is that everyone is using the same official number.
Step 2: the Course Handicap
A course is not equally hard for everyone. The Course Rating says what a scratch golfer is expected to shoot from a tee, and the Slope Rating says how much harder the course plays for a bogey golfer; 113 is the standard slope. Your Course Handicap converts the Index for the tee you are playing:
For example, a 10.4 Index on a tee with a slope of 130, a rating of 72.1 and a par of 72 gives 10.4 x 130 / 113 + (72.1 - 72) = 11.96 + 0.1 = 12.06. Keep the decimals for now; rounding comes last.
Step 3: the allowance and the Playing Handicap
Different formats use different shares of the Course Handicap. The recommended allowances in the World Handicap System include 95% for individual stroke play and 100% for individual match play, and groups often use 100% for their own money games. The Playing Handicap is the Course Handicap multiplied by the allowance and then rounded to a whole number, with a half rounded up.
Using the example above at 95%: 12.06 x 0.95 = 11.46, which rounds to 11. At 100% it is 12. Apply the allowance to the unrounded number and round once at the end; rounding twice slowly drifts the answer.
Step 4: which holes get the strokes
Every hole on the scorecard carries a stroke index from 1 (the hardest hole for most golfers) to 18 (the easiest). Strokes are given on the lowest-numbered holes first. A Playing Handicap of 11 receives one stroke on each of the holes with stroke index 1 to 11. A Playing Handicap of 20 receives a stroke on every hole and a second on the two hardest, indexes 1 and 2. A plus handicap works in reverse: a +2 gives a stroke back on the two easiest holes.
On the scorecard the strokes are usually shown as dots beside the score box. Subtract the dots from the gross score to get the net score for the hole.
Strokes off the low
Most money games between a few friends use strokes off the low: the golfer with the lowest Playing Handicap plays at zero, and everyone else receives the difference between their handicap and the lowest. In a group of 6, 11, 14 and 20, the 6 plays scratch and the others receive 5, 8 and 14 strokes. This keeps the strokes small, which most players find fairer in a head-to-head game than handing out the full number to each person.
Off the low has one subtle point: you choose who counts as the low. In a Nassau between two golfers it is the lower of the two. In a four-golfer game it is the lowest of the four. The same player can therefore receive a different number of strokes in two games on the same day, and that is correct.
Nine holes and partial rounds
If you play nine holes of an eighteen-hole card, the strokes are still ranked by the printed stroke index, but only the nine holes you play are in play, so each hole is re-ranked 1 to 9 among those nine. The nine-hole Course Handicap uses half of the Handicap Index, to a tenth, with the nine-hole slope and rating. A good scorekeeper does this for you, but it explains why the dots on a nine-hole round can look different from the full card.
Par 3s and other house rules
Some groups give no strokes on par 3s, or fewer strokes on holes that are short, because a stroke there is worth more than it looks. That is a house rule, not part of the handicap system, so the extra strokes it removes have to go somewhere else on the card. Agree it on the first tee and write it down.
Common mistakes
- Rounding the Index or the Course Handicap before applying the allowance.
- Using the wrong tee: the Slope and Rating belong to the tee you play, not the one you usually play.
- Giving strokes in order of hole number instead of stroke index.
- Forgetting that a plus handicap gives strokes back.
- Mixing the full Playing Handicap and off the low in the same game.
Check your numbers
The handicap strokes calculator turns an Index into a Course Handicap, a Playing Handicap and the strokes per hole, and the strokes off the low calculator works out the differences for a whole group. For the way a scorekeeper uses these numbers in each game, see how the numbers are worked out.
Handicaps are the one place where a game can be argued about forever, so be strict in the other places. Use the official Index, agree the allowance and the low before you tee off, and let the dots on the card do the work.