Statistics Calculators

Standard Deviation Calculator

Calculate the sample and population standard deviation of a dataset — a measure of how spread out the values are.

Sample standard deviation —

Population standard deviation —

Mean —

About the Standard Deviation Calculator

Standard deviation measures how spread out values in a dataset are relative to the mean. A low standard deviation means values cluster close to the mean; a high one means they're spread widely.

Formula: Sample: s = √(∑(x − x̄)² ÷ (n − 1)) · Population: σ = √(∑(x − μ)² ÷ n)

Use the sample formula (dividing by n − 1) when your data is a sample from a larger population — the most common case. Use the population formula when your data represents the entire population.