Percentile Calculator
Find the value at a given percentile in a data set. Enter your numbers separated by commas or spaces.
How to use the percentile calculator
- Enter your numbers in the field, separated by commas or spaces.
- Enter which percentile you want to find (e.g. 90 for the 90th percentile).
- The value at the selected percentile updates automatically.
What is a percentile?
The n-th percentile in a data set is the value below which (or equal to which) n percent of the data falls. For example, the 90th percentile means 90% of the values in the data set are equal to or lower. This calculator uses linear interpolation between the nearest ranks when the exact percentile doesn't land directly on an existing data point.
A percentile is not a percentage
Being at the 90th percentile does not mean you scored 90 percent. It means you are above 90 percent of the others in the dataset. A student can get 55 percent correct on a hard test and still sit at the 90th percentile, while 95 percent correct on an easy test might give a far lower percentile.
A percentile therefore says something about your position within a distribution, not about the level itself. That makes it useful for comparing across tests of differing difficulty, and it is why growth charts for children, standardised tests and salary statistics are usually reported in percentiles rather than raw values.
Worked example: for the series 1 to 10, the 90th percentile sits at rank 0.90 × (10 − 1) + 1 = 9.1. Since 9.1 is not a whole number, the result is interpolated between the 9th and 10th values: 9 + 0.1 × (10 − 9) = 9.10. A percentile is therefore not necessarily a value that appears in the data set — it is the position below which 90 % of observations fall.
Frequently asked questions
What's the difference between percentile and quartile?
Quartiles are specific percentiles — Q1 is the 25th percentile, the median is the 50th percentile, and Q3 is the 75th percentile. Percentiles give more fine-grained information, since you can find the value at any percentage, not just these three.
What does it mean to be in the 90th percentile?
It means the value is equal to or higher than 90% of all other values in the data set — only 10% of the data lies above this value.
Where are percentiles used in practice?
Percentiles are widely used in statistics, medicine (e.g. growth and height charts for children), and performance measurement (e.g. "95th percentile response time" for a system).