# Standard Deviation Calculator

Here are the step-by-step calculations to work out the Standard Deviation (see below for formulas).

Enter your numbers below, the answer is calculated "live":

images/std-dev1.js

When your data is the whole population the formula is:

**"Population** Standard Deviation**"**

When your data is a sample the formula is:

**"Sample** Standard Deviation**"**

The important difference is "N-1" instead of "N" ... read more at Standard Deviation Formulas.