Stroke Index in handicap golf rounds

Stroke index is an unique numerical value assigned to each hole on a golf course. It specifies the difficulty of a particular hole compared to other holes on the same course. For an 18-hole course, the index values range from 1 to 18. Index 1 indicates the most difficult hole and index 18 indicates the easiest hole. For a 9-hole course, the index values range from 1 to 9.

On scorecards stroke indexes are sometimes labeled as Index, SI (short for Stroke Index), HCP or HDCP.

Stroke index on scorecard

Stroke Index in 18-hole play

Stroke indexes are used to assign handicap strokes that golfers receive in handicap rounds: stroke play net, Stableford net, etc. Handicap strokes are assigned to individual holes in the order of their indexes, starting from the most difficult hole (SI = 1). This means that:

a player with a Course/Playing Handicap of 8 receives one handicap strokes on holes with stroke indexes from 1 to 8,
a player with a Course/Playing Handicap of 15 receives one handicap strokes on holes with stroke indexes from 1 to 15, etc.

The players with a handicaps between 18 and 36, receive one stroke on all holes, and subsequent strokes are allocated to holes according to their indexes in ascending order. As a consequence of this:

a player with a Course/Playing Handicap of 21 (18+3) receives two handicap strokes on holes with stroke indexes from 1 to 3, and one stroke on holes with stroke indexes from 4 to 18,
a player with a Course/Playing Handicap of 30 (18+12) receives two handicap strokes on holes with stroke indexes from 1 to 12, and one stroke on holes with stroke indexes from 13 to 18,

Strokes for higher handicapers are allocated in the same way:

a player with a Course/Playing Handicap of 41 (18+18+5) receives three handicap strokes on holes with stroke indexes from 1 to 5, and two strokes on holes with stroke indexes from 6 to 18,

Stroke Index in 9-hole play

During a 9-hole round, strokes are assigned in the same way, but using only stroke indexes from 1 to 9:

a player with a Course/ Playing Handicap (for 9 holes) of 15 (9+6) receives two handicap strokes on holes with stroke indexes from 1 to 6, and one stroke on holes with indexes from 7 to 9,
a player with a Course/ Playing Handicap (for 9 holes) of 21 (9+9+3) receives three handicap strokes on holes with stroke indexes from 1 to 3, and two strokes on holes with indexes from 4 to 9,

If a golfer is playing a 9-hole round on an 18-hole course or an 18-hole round on a 9-hole course, the indexes listed on the scorecard must be converted accordingly. There are two calculators available for converting stroke indexes: