Golf Handicap Explained: The Current Formula

What the number measures

A Handicap Index measures a golfer’s demonstrated playing ability — their potential on a good day. That is the whole point of it: because the number reflects what each player is capable of, golfers of very different ability can compete fairly in the same match.

It is not simply your average score over par. Most of your rounds will be worse than your Index suggests, and that is normal. The system deliberately builds the number from your better rounds, because those are the rounds that show what you can do.

The Index is portable: it is the same number everywhere. When you play a particular course, it is converted into a Course Handicap for that course and those tees (covered near the bottom of this page).

Step one: each round becomes a Score Differential

Every posted round is converted into a Score Differential — a single number that says how well you played, after allowing for the difficulty of the course. The formula is:

Adjusted Gross Score

Your total score for the round, after one protection is applied: each hole is capped at net double bogey — that is, double bogey plus any handicap strokes you get on that hole. One disaster hole cannot wreck the number, because anything above that cap is simply cut back to the cap before the score is used.

Course Rating

The score a scratch golfer (a player with a Handicap Index of 0.0) is expected to shoot from those tees. It is printed on the scorecard and in the course’s details — it might be, say, 71.2 on a par-72 course.

Slope Rating

A number from 55 to 155 that measures how much harder the course plays for a bogey golfer than for a scratch golfer. The higher the Slope, the bigger the gap. 113 is the standard — a course with a Slope of 113 is of standard relative difficulty, so the formula’s first fraction comes out at exactly 1.

PCC adjustment

PCC stands for the Playing Conditions Calculation. It is an adjustment of −1 to +3 that the system sometimes applies when unusual weather or course conditions made scoring noticeably harder or easier that day. You never work it out yourself — the system adds it when it posts your score. For any hand calculation, use 0.

Step two: the best 8 of your last 20

Once your rounds have become differentials, the Index itself is simple:

Only the eight lowest count. The other twelve — your off days, the windy rounds, the new-course struggles — are set aside. That is why the Index reflects your potential rather than your typical day.

The case this page covers

This page covers the standard case — a full record of 20 scores. The Index is the average of the lowest 8 differentials from those 20, as set out above.

Try the arithmetic yourself

Both tools below run entirely on your device. Nothing you type is sent anywhere or saved.

On a real course: your Course Handicap

Your Index is the portable number. On a specific course, from specific tees, it converts into a Course Handicap — the actual number of strokes you play off that day:

Example: an Index of 14.8 on the course from earlier (Slope 128, Course Rating 71.2, par 72) gives 14.8 × (128 ÷ 113) = 16.8, then 16.8 + (71.2 − 72) = 16.0 — a Course Handicap of 16. Your net score is then your gross score minus the Course Handicap: shoot 92 and your net score is 92 − 16 = 76.