Try this

=(A2/B2)/(C2/B2)
Format as %

Where

A2= actual attendance - 23
B2= Max attendance - 30
C2= optimum attandance - 28



Mike

"emaypsu" wrote:

John was in school for 23 out of 30 days last month, which means he was in
school 76.66% of the days. We expected him to be in school for 28 days, or
93.33% of the days. How do I calculate the variance in the percentages?