Percentile Calculator
The value at any percentile of a list of numbers (quartiles included), and the percentile rank of a value you enter.
Sort the values; the pth percentile is the value below which p% of the data lies.
How the percentile calculator works
Sort the values; the pth percentile is the value below which p% of the data lies. This calculator uses linear interpolation between order statistics (the method most spreadsheets use, rank = (n − 1) × p/100 + 1). The percentile rank of a value is the share of data below it.
Formula: rank = (n − 1) × p/100 + 1, interpolated between neighbours
Worked examples
| Inputs | Value at the percentile | Note |
|---|---|---|
| 90th percentile of the sample list | 76.5 | 76.5 |
| median | 52.5 | 52.5 |
FAQFrequently asked questions
What is a percentile?
The value below which a given percentage of the data falls: the 90th percentile is higher than 90% of the values.
Why do different tools give different percentiles?
There are several interpolation conventions; this one matches Excel's PERCENTILE.INC and most statistics packages' default.
What is the interquartile range?
Q3 − Q1: the spread of the middle half of the data, a robust alternative to standard deviation.
What is a percentile rank?
The share of values below a given value (ties count half).
Is the 50th percentile the mean?
No — it is the median. They coincide only for symmetric data.
Where these figures come from
- NIST Digital Library of Mathematical Functions — reference definitions for elementary and special functions
- Wolfram MathWorld — definitions and formulas for every topic on this page
- NIST/SEMATECH e-Handbook of Statistical Methods — the statistical formulas (mean, variance, z, confidence intervals, sample size)
- Common Core State Standards — Mathematics — the terms and methods taught in US schools
Last checked: September 2026. Formulas are fixed by mathematics and do not change with tax years or regulations.