About this calculator
What a percentile means
The kth percentile is a value with about k% of the data below it. Scoring at the 85th percentile means you did better than about 85% of the people in the group. It does not mean you got 85% of the questions right.
The method used here
To find the value at the kth percentile, put the data in order and compute c = n·k ÷ 100. If c is not a whole number, round up and use the value in that position. If c is a whole number, average the values in positions c and c + 1. The percentile rank of a value is (number of values below it ÷ n) × 100.
Textbooks and software use several slightly different percentile rules, so small differences from other tools are normal.