PlayThru Live Golf Event Scoring

How do handicaps work for 9-hole and 18-hole golf event

Keith Moehring
November 18, 2023
Create a Free PlayThru Account

Applying handicaps to a round of golf isn't not confusing. This is especially true when switching between 9-hole and 18-hole rounds. The course and player information used is different. 

Below is a breakdown of how handicaps are calculated and what information you need to enter into PlayThru so that handicaps are applied correctly. 

Handicap Index or Course Handicap

A handicap index is a number that represents a player's ability, while a course handicap is the number of strokes a player receives from a set of tees. Much of this article applies to how course handicaps are calculated.

A player's handicap index is converted to a course handicap when they play, taking into account the difficulty of the course and tees played.  PlayThu will calculate each player's course handicap if the "Adjust Handicap' circle in the Event Tab is selected in the Event Tab of the Outing Organizer.

You don't necessarily need to do this. You can play just using handicap indexes. But, if adjusting your handicaps for the course, read on. 

Course Handicaps for 18-Hole Rounds

To calculate a player's course handicap, you need the player's handicap index, the course Slope Rating, the course Rating, and the total par for the course. These values are then applied using the following formula.

Course Handicap= Handicap Index x (Slope Rating / 113) + (Course Rating - Total Par)

For example, if I'm a handicap index of 10 and playing on a course with a slope rating of 121, a course rating of 73 and a total par of 72, my course handicap would be 11.7 (rounded to 12). 

10 x (121 / 113) + (73 - 72) = 11.7

PlayThru will do this calculation automatically within our system if you check the "Adjust Handicap" circle in the Event Tab of the Outing Organizer. 

Course Handicaps for 9-Hole Rounds

If you're playing a 9-hole round, you need to make some adjustments. A golfer with a 12 handicap index shouldn't get all their strokes over 9 holes. 

All courses have separate Slope Ratings and Course Ratings for each 9 and the full 18. Generally speaking, the 9-hole ratings are about half the ratings for the full 18, but not exactly. Usually, one 9 is harder than another, and the slope and course ratings reflect that. 

The 9-hole ratings sometimes appear on the course's scorecard, but more often than not, you need to ask the course for that information. 

To adjust a golfer's handicap index for a 9-hole round, you need to use the following formula. 

Course Handicap = (Handicap / 2) x (9-hole Slope / 113) + (9-hole Course Rating - Total Par)

For example, I'm still a 10 handicap and playing on a 9-hole course with a slope of 61.5 and a course rating of 37 with a par of 36. My adjusted handicap will be 3.7 rounded to 4. 

(10 / 2) x (61.5 / 113) + (37 - 36) = 3.7

PlayThru will NOT adjust handicap indexes or the slope and course ratings automatically. You'll need to enter the correct information manually. However, PlayThru will apply the correct formula to adjust golfer handicap indexes for the course if you check the "Adjust Handicap" circle in the Event Tab of the Outing Organizer. 

In other words, you enter the following:

  • Handicap: golfer handicap / 2 (Golfer Tab)
  • 9-hole slope rating (Course Tab)
  • 9-hole course rating (Course Tab)


Rounding Rules

In both 18-hole and 9-hole calculations, the final Course Handicap is rounded to the nearest whole number, with .5 rounded upwards. This rule is important for adjusting maximum hole scores and calculating score differentials, ensuring consistency and fairness in your game.

USGA v. World Handicap System

It's important to note, the above formulas are contingent on what set of rules you follow. The above are the rules as defined by the USGA. However, the World Handicap System sometimes uses different formulas. Namely, they don't add (course rating - par).  


Emails are sent every other week.