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Percentile Calculator

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Enter a data set to find the value at any percentile, or find what percentile a specific value ranks at.

Percentile Calculator

Live
Value at the 90th percentile
89.5
Uses linear interpolation between ranked values - the same method used by Excel's PERCENTILE function.

The formula

Sort the data set from smallest to largest Rank = (Percentile / 100) x (Count - 1) Interpolate between the values at that rank
Example

A 12-value data set, finding the 90th percentile: rank = 0.90 x 11 = 9.9, interpolating between the 10th and 11th sorted values gives 89.5.

Step-by-step guide

  1. Enter your data set, separated by commas.
  2. Choose what you want to find - a value at a given percentile, or the percentile rank of a specific value.
  3. Read the result.

Why percentile isn't the same as percentage

A common mix-up: scoring "90%" on a test means getting 90% of the questions right, but ranking at the "90th percentile" means scoring better than 90% of everyone else who took it - two completely different measurements that happen to use similar-sounding numbers. It's entirely possible to score 95% correct but rank at only the 60th percentile if the test was easy and most people also scored well, which is exactly why standardized tests report percentile rank separately from raw score percentage.

Common mistakes

Confusing percentile with percentage - they measure fundamentally different things, even though both are expressed as numbers up to 100.
Expecting the exact same percentile result from every calculator or spreadsheet function - there are several slightly different, all mathematically valid interpolation methods in common use, which can shift the result by a small amount.

Frequently asked questions

What does the 50th percentile represent?

The 50th percentile is the median - the middle value of the data set, where half the values fall below and half fall above.

Why might this give a slightly different answer than another tool?

There are several different, equally valid statistical methods for calculating percentiles (this one uses linear interpolation, matching Excel's default PERCENTILE function) - small differences between tools are usually just a different method choice, not an error.

How is this related to a z-score?

This calculator finds a percentile directly from your actual data set. Our Z-Score Calculator instead estimates a percentile assuming the data follows a normal (bell curve) distribution - useful when you know the mean and standard deviation but not every individual data point.

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