Other forms: percentiles
A percentile is a way of comparing or ranking a set of data, usually people's test scores. Typically, the lowest reported percentile is the 1st, and the highest is the 99th.
To calculate a percentile, all the values (e.g., test scores) are ordered from lowest to highest, divided into groups, and compared on a 100-point scale. The 50th percentile represents the median score; half the scores are lower, and half the scores are higher. If you rank in the 85th percentile, that means you scored equal to or better than 85 percent of the test takers. Good for you! It does not mean, however, that you got 85 percent of the questions correct. A percentile is a comparative ranking only, so it depends on how other people scored on the test, too.