Percentile Calculator

Enter your numbers and a percentile to find the value at that point.

This result is an estimate only. Double-check important figures before relying on them.

How it is calculated

Sort the numbers from smallest to largest
Rank = (percentile ÷ 100) × (count − 1) + 1
If the rank is not a whole number, interpolate between the two values on either side

For the middle value on its own, use the mean, median and mode calculator.

Worked example

The 40th percentile of 15, 20, 35, 40, 50:

Rank = 0.4 × 4 + 1 = 2.6
Value = 20 + 0.6 × (35 − 20) = 29

Why your number may differ

Other tools use exclusive or nearest-rank methods that can give a different answer, mostly on short lists. Check which one your course or software uses.

Frequently asked questions

What is a percentile?

It is the value below which a given percentage of the data falls. The 90th percentile is higher than 90% of the values.

Which method does this use?

Linear interpolation between the nearest two ranks, which matches Excel’s PERCENTILE.INC and the default in NumPy. Other textbooks use slightly different rules.

Is the median the 50th percentile?

Yes. The 50th percentile is the median.