Standard Deviation Calculator

Calculate mean, variance, and standard deviation for any data set.

Data (comma or space separated)

Population & Sample

Calculate both population (N) and sample (N-1) standard deviation.

Complete Statistics

Get mean, median, mode, variance, range, and standard deviation in one calculation.

Step-by-Step

See the calculation steps to understand how standard deviation is computed.

FAQ

What is standard deviation?

Standard deviation measures how spread out numbers are from the mean. A low SD means data points are close to the mean; a high SD means they are spread over a wider range.

Population vs sample standard deviation?

Population SD divides by N (total count). Sample SD divides by N-1 (Bessel's correction) to account for estimating from a subset.