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-dev.js
When your data is the whole population the formula is:
![square root of [ (1/N) times Sigma i=1 to N of (xi - mu)^2 ]](images/standard-deviation-formula.svg)
"Population Standard Deviation"
When your data is a sample the formula is:
![square root of [ (1/(N-1)) times Sigma i=1 to N of (xi - xbar)^2 ]](images/standard-deviation-sample.svg)
"Sample Standard Deviation"
The important difference is "N−1" instead of "N", see Standard Deviation Formulas.