Standard Deviation Calculator

How to calculate standard deviation

1. Paste your numbers, separated by spaces, commas or line breaks.
2. Choose Sample if the numbers are a sample of a larger group, or Population if they are the whole group.
3. The standard deviation appears with the mean, variance, standard error, median, quartiles and range.

Frequently asked questions

What is the difference between sample and population?

A sample standard deviation divides by n − 1 and a population one by n. Use the sample version unless your numbers really are every member of the group; it is the usual choice in science and statistics.

What is the formula?

Standard deviation = √(Σ(x − mean)² ÷ (n − 1)) for a sample. Square it and you have the variance.

What is the standard error?

The standard deviation divided by √n. It estimates how much the mean itself would vary between samples, and it is what error bars on a mean usually show.

Are my numbers sent anywhere?

No. Everything is worked out in your browser and nothing is stored or uploaded.