What does standard deviation tell me?

How spread out the numbers are around the average. A small value means they cluster close together.

Sample or population — which should I use?

Use sample if the data is a subset of something larger, which is the usual case.

Enter your numbers to get both the sample and the population standard deviation, plus variance, mean and more.

Numbers (separated by commas, spaces or new lines)

Full descriptive statistics for any data set: sample and population standard deviation, variance, mean, median, mode, sum, min, max and range.

variance = Σ(x − mean)² ÷ N (population) or ÷ (N−1) (sample); standard deviation = √variance.

Common questions about Standard Deviation Calculator

We use the standard published formula for this calculation, and we show the working so you can check it.

Spotted a mistake? Tell us and we'll check it within a few days. See how we check our calculators.