How this calculation works
Enter the most recent twenty posted differentials, including any adjustments already applied to those entries. The optional established Low Handicap Index applies the upward soft and hard caps before the modeled index is used in the course calculation.
Index = average of the lowest 8 of 20 posted differentials. Course handicap = index × slope / 113 + course rating − par.A worked example
Eight scores of 10 and twelve higher differentials give a best-eight average of 10. With slope 113 and rating equal to par, the modeled course handicap is 10.
Good to know
This is the 20-score USGA workflow for an 18-hole round. It uses posted differentials and any supplied low index. Exceptional-score adjustments and handicap committee decisions belong in the official record.
Reference: USGA Rules of Handicapping, rules 5 and 6 (opens in a new tab) ↗
How the inputs affect the result
Take course rating, slope and par from the same set of tees. For playing handicap, the allowance is applied to the unrounded course result before the final rounding.
A tee change alters course handicap while the differential history remains the same.
Where the calculation applies
This is the 20-score USGA workflow for an 18-hole round. It uses posted differentials and any supplied low index. Exceptional-score adjustments and handicap committee decisions belong in the official record.
For a related calculation, see the Mean median mode variance and standard deviation calculator.
Read more: USGA Rules of Handicapping, rules 5 and 6 (opens in a new tab) ↗
A few questions, answered
What happens with fewer than twenty differentials?
The calculation requires exactly twenty. Use the USGA rules for the separate short-record procedure.
What does the “Higher slope with rating above par” setting illustrate?
A tee change alters course handicap while the differential history remains the same.