Can I submit a 9-hole score for handicap?

Yes. 9-hole scores count in both competitions and general play, as long as you play all the holes of a rated 9-hole course (for example, the front nine or back nine of your course) and meet the usual conditions: pre-registered, played under the Rules of Golf, with a marker.

How it's converted (Rules of Handicapping 2024): your 9-hole score is turned straight into an 18-hole Score Differential:

9-hole Score Differential + expected 9-hole Score Differential = 18-hole Score Differential

The expected score is based on your Handicap Index over a course of standard difficulty, so a player off 10.0 has a lower expected score than a player off 15.0.

9-hole Course Handicap:

Course Handicap = (Handicap Index ÷ 2) × (9-hole Slope Rating ÷ 113) + (9-hole Course Rating − 9-hole par)

For new golfers: complete 9-hole and 18-hole rounds can be combined to make up the 54 holes needed for your first Handicap Index.