Rank and value
Percentile Calculator: Percentile Rank and Value
Find the percentile rank of a value in your data, or the value at any percentile, with the formula shown. Paste numbers separated by commas, spaces or lines.
Every value is calculated in your browser from the standard normal distribution (Marsaglia’s series for Φ) and rounded to four decimals; the tables were checked cell by cell against an independent calculation. These tables give the area to the left of z. Some textbooks, including the NIST handbook, print the area from 0 to z instead, which is the left area minus 0.5 for positive z.
Two ways to use percentiles
A percentile rank says where a value sits: the percent of values below it plus half of the values equal to it. In the example data, 78 has 7 values below and 1 equal out of 12, a percentile rank of 62.5. The value at a percentile works the other way: the 90th percentile is found by linear interpolation between sorted values, the same method as Excel’s PERCENTILE.INC.
- Other textbooks use slightly different definitions, so small differences between tools are normal.
- For a value from a normal distribution, use the z-score calculator instead.
Common questions
Is the 90th percentile the same as 90%?
No. Scoring at the 90th percentile means doing as well as or better than about 90% of the group, whatever your raw score was.
Why do different calculators give different percentiles?
There are several accepted definitions of a percentile for a small data set. They agree closely for large data sets.
The studio notebook
A useful place to begin.
Clear steps, considered details, and ideas you can put to use.
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