Standard Deviation Calculator

How It Works

The calculator first finds the mean, then measures how far each value sits from it, squares those distances so positives and negatives do not cancel, and adds them up. Dividing that total gives the variance, and its square root is the standard deviation. It reports two versions: the population figure divides by the full count, while the sample figure divides by one less — the correction statisticians use when the data is only a sample of a larger group.

σ = √(Σ(x − μ)² / N)  [population]
s = √(Σ(x − x̄)² / (n−1))  [sample]

Examples

Frequently Asked Questions