Rather than use our raw scores to find our best 10 out of the last 20 for calculation, the GHIN system calculates a differential. This takes into account the course slope rating so your Index is not lower than someone with the same ability who plays a different course that’s easier. If your handicap is a 33.2, your course handicap at Cross Creek would be 33 and your course handicap at the OGA course would be 37. If you score 105 at Cross Creek and 109 at the OGA Course you might think you did better at Cross Creek but you would actually be scoring better at OGA given how much more difficult it is. To make these scores comparable for calculation the Handicap Differential is calculated for each score.

The Handicap Differential is computed using the following formula:

Handicap Differential = (Adjusted Gross Score - Course Rating) X 113 ÷ Slope Rating

Example using the 105 at Cross Creek and the 109 at the OGA Course

Cross Creek (105-67.6) x 113 / 113 = 36.8 slightly above par

OGA (109-72.2) x 113 / 128 = 32.5 below par!

To calculate your index the GHIN system then selects the lowest Handicap Differentials. If more than 20 scores have been entered, the 10 best differentials of the 20 most recent scores are used for the calculation.

The next step is a simple average of the 10 best of the last 20 Differentials.

Although the purpose of a handicap is to level the playing field, there is still a minor adjustment made so that you don’t get the entire amount of the average Differential. Instead they multiply by 96%. If the average of your best 10 differentials was 33.6, you might expect a handicap index of 33.6 but instead you’ll get 32.2 because of this factor.

To come up with the index, they delete the digits after the tenths for the number calculated with the 96%. They do NOT round off to the nearest tenths place. That means that if that number is 32.40 or 32.48 your Index is still 32.4

**Calculation of the Index****THIS IS THE MATH PART OF THIS OVERVIEW****YOU WILL NEVER NEED TO USE THIS MATH****First: You post your ESC scores****Second: The System calculates a Handicap Differential for each score**Rather than use our raw scores to find our best 10 out of the last 20 for calculation, the GHIN system calculates a differential. This takes into account the course slope rating so your Index is not lower than someone with the same ability who plays a different course that’s easier. If your handicap is a 33.2, your course handicap at Cross Creek would be 33 and your course handicap at the OGA course would be 37. If you score 105 at Cross Creek and 109 at the OGA Course you might think you did better at Cross Creek but you would actually be scoring better at OGA given how much more difficult it is. To make these scores comparable for calculation the Handicap Differential is calculated for each score.

The Handicap Differential is computed using the following formula:

Handicap Differential = (Adjusted Gross Score - Course Rating) X 113 ÷ Slope Rating

Example using the 105 at Cross Creek and the 109 at the OGA Course

Cross Creek (105-67.6) x 113 / 113 = 36.8 slightly above par

OGA (109-72.2) x 113 / 128 = 32.5 below par!

**Third: The Lowest Handicap Differentials are Identified**To calculate your index the GHIN system then selects the lowest Handicap Differentials. If more than 20 scores have been entered, the 10 best differentials of the 20 most recent scores are used for the calculation.

**Next: Average of the Lowest Handicap Differentials**The next step is a simple average of the 10 best of the last 20 Differentials.

**Then: The Average of the best ten differentials is multiplied by 0.96 or 96%**Although the purpose of a handicap is to level the playing field, there is still a minor adjustment made so that you don’t get the entire amount of the average Differential. Instead they multiply by 96%. If the average of your best 10 differentials was 33.6, you might expect a handicap index of 33.6 but instead you’ll get 32.2 because of this factor.

**Finally: the Index is established by truncating (deleting)****Numbers to the Right of Tenths**To come up with the index, they delete the digits after the tenths for the number calculated with the 96%. They do NOT round off to the nearest tenths place. That means that if that number is 32.40 or 32.48 your Index is still 32.4