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":

When your data is the whole population the formula is:
(The "Population Standard Deviation")

  square root of [ (1/N) times Sigma i=1 to N of (xi - mu)^2 ]
When your data is a sample the formula is:
(The "Sample Standard Deviation")
  square root of [ (1/(N-1)) times Sigma i=1 to N of (xi - xbar)^2 ]

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