Two opposite questions
A percentile goes from a percentage to a value: what score is at the 90th percentile? A percentile rank goes from a value to a percentage: what percentile is a score of 75? This calculator answers both. See percentile vs percentile rank.
Worked example
For the 15 exam scores shown, the 90th percentile is 86.4 by the inclusive method and 90.8 by the exclusive one. A score of 75 appears twice: 46.7% of scores are below it and 60.0% are at or below it, so its midpoint rank is 53.3.
Why the methods differ
With limited data, a percentile often falls between two values, and there are several rules for choosing. The inclusive method matches Excel’s PERCENTILE.INC and R’s default, and the exclusive method matches PERCENTILE.EXC and SPSS. The gap shrinks with more data. Results match NumPy’s percentile and SciPy’s percentileofscore.
For normally distributed scores with a known mean and SD, use the z-score calculator instead. For the 25th and 75th percentiles, see the quartile calculator.
Frequently asked questions
How do you calculate a percentile?
Sort the data, compute the position from the percentile and n, and interpolate between neighbouring values if the position is not a whole number.
What is the difference between percentile and percentage?
A percentage of 80% describes your own score out of the total. The 80th percentile means you scored at or above 80% of people.
How do I calculate a percentile in Excel?
Use =PERCENTILE.INC(range, 0.9) for the 90th percentile and =PERCENTRANK.INC(range, value) for a rank.