Percentile Calculator
Find the percentile rank of a value, or the value sitting at a given percentile of your data.
Using the “values below” convention: 2 of 5 values are less than 30.
A percentile tells you what share of a dataset falls below a given value. The percentile rank of a value is (number of values below it ÷ total) × 100. In the set 10, 20, 30, 40, 50, two of the five values are below 30, so 30 sits at the (2 ÷ 5) × 100 = 40th percentile.
What a percentile means
A percentile locates a value within a distribution by the proportion of data beneath it. If you score at the 90th percentile, roughly 90% of the other values are below yours. Percentiles are rank-based, so they describe position rather than distance — the gap between the 50th and 60th percentile need not match the gap between the 80th and 90th. This tool works two ways: it gives the percentile rank of a value you choose, and it gives the value located at a percentile you choose.
this tool uses the “values strictly below” convention
Worked example
Five values: 10, 20, 30, 40, 50.
- 1 Sort the data. Ascending: 10, 20, 30, 40, 50. Sorting is required before counting or interpolating.
- 2 For a rank, count values below your target. Two values (10 and 20) are below 30, out of five total: (2 ÷ 5) × 100 = 40th percentile.
- 3 For a value at percentile P, interpolate. Rank = (P ÷ 100)(n − 1). For P = 25: (25 ÷ 100)(5 − 1) = 1, the index-1 value, which is 20.
Quartiles as percentiles
The three quartiles that split a dataset into four equal parts.
| Percentile | Name | Splits off |
|---|---|---|
| 25th | First quartile (Q1) | Lowest 25% of the data |
| 50th | Median (Q2) | Lower half from the upper half |
| 75th | Third quartile (Q3) | Highest 25% of the data |
Why answers can differ between tools
There is no single percentile formula. Spreadsheets and statistics packages implement several different methods, so the same data and the same percentile can yield slightly different values. Excel alone ships two functions — PERCENTILE.INC and PERCENTILE.EXC — and statistical software offers up to nine recognised interpolation schemes. The differences are largest for small datasets and shrink as the sample grows.
What this tool does. For a value’s percentile rank it counts values strictly below the target and divides by the total. For the value at a percentile it sorts the data and applies linear interpolation with rank = (P ÷ 100)(n − 1), interpolating between the two neighbouring sorted values — the same method as Excel’s PERCENTILE.INC. If you need to match another package exactly, check which method it uses before comparing numbers.