Percentile Calculator

Find the value at any percentile of your data (for example, the 90th percentile), or the percentile rank of a particular value. The calculator shows the rank position and interpolation.

90th percentile
92.1
Nearest-rank method
93
n
14

Step-by-step working

  1. Sort the data55, 61, 64, 68, 70, 72, 75, 78, 81, 84, 88, 90, 93, 97
  2. Find the position: (n − 1) × p + 1 (counting from 1)(14 − 1) × 0.9 + 1 = 12.7
  3. Interpolate between the 12th and 13th values90 + 0.7 × (93 − 90) = 92.1

Formula position = (n − 1) × p + 1 (linear interpolation) percentile rank = (below + ½·equal) ÷ n × 100

Ask the tutor about your result

An AI tutor reads your inputs and results above and explains them in plain English. The numbers come from the calculator; the explanation is AI-written, so check it against your notes.

Percentile vs percentile rank

The kth percentile is a value: k% of the data fall at or below it. A percentile rank goes the other way: given a score, what percentage of scores are below it? Scoring in the 90th percentile on a test means you did better than about 90% of test takers; it says nothing about the percentage of questions you got right.

Which method?

There is no single definition for small data sets. This calculator uses linear interpolation (Excel’s PERCENTILE.INC, R’s default type 7) and also shows the simpler nearest-rank method. For large data sets the methods agree closely. For normally distributed quantities with a known mean and SD, use the z-score calculator to get a percentile directly.

Frequently asked questions

Is the 50th percentile the median?

Yes. The 25th and 75th percentiles are Q1 and Q3 (though quartile methods can differ slightly from percentile methods).

Can a percentile be 100?

With the inclusive method, the 100th percentile is the maximum value. As a percentile rank, it is usually capped just below 100 because a value cannot be above itself.