Calculate Mean, Median & Standard Deviation

A single average rarely describes a data set well, two very different sets can share the same mean. This tool gives seven numbers at once: count, sum, arithmetic mean, median (the middle value after sorting), minimum, maximum and standard deviation. Separate the values with commas, spaces, semicolons, newlines or pipes; whatever you copy out of a spreadsheet or editor is accepted, and anything non-numeric is ignored. The standard deviation is the population form (dividing by n), not the sample form (n−1).

This tool runs entirely in your browser. No data is sent to any server.

How to use it

1. 1

   Paste your list of numbers into the box; any separator works.

2. 2

   The cards below fill in immediately.

3. 3

   To see the effect of one value, change it and watch the mean and standard deviation move together.

Frequently asked questions

What is the difference between mean and median?

The mean is the sum divided by the count and is sensitive to very large values. The median is the middle value of the sorted list and is not dragged by one outlier; a big gap between the two usually means an extreme value is present.

Is the standard deviation for a population or a sample?

Population: it divides by n. If your numbers are a sample of a larger group and you want an estimate, the sample standard deviation divides by n−1 and comes out slightly larger.

How many numbers can I enter?

There is no hard limit; a few thousand values process quickly in the browser. Non-numeric data such as headings or text is ignored.