Math

Standard Deviation Calculator

Standard deviation calculator with mean, variance, minimum, maximum, and sample or population formulas.

Standard deviation measures how spread out values are around their mean. Choose population when the list represents the entire group and sample when it represents observations used to estimate a larger population.

Sample standard deviation divides squared deviations by n−1; population standard deviation divides by n.

Frequently asked questions

When should I use sample standard deviation?

Use it when observations are a sample intended to estimate variability in a larger population.

Can standard deviation be negative?

No. It is the square root of variance and is never negative.

What does a value of zero mean?

Every observation in the list is identical.