Hello ,

Actually percentage is quite different from percentile and people often get confused with both of these and mistaken percentile as percentage.

Percentage is based on your marks simply ,

Percentage= (Your marks /Total marks )×100

But for percentile ,  R= P/100(n+1)where r is the rank order of your score and p is the percentile rank and n is the no of scores in distribution. 

Thank you.