Standard Deviation Calculator

Calculate population and sample standard deviation with complete step-by-step work

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Population Standard Deviation (σ)

About the Standard Deviation Calculator

This calculator computes key statistical measures for any dataset: count, sum, mean, variance, and standard deviation for both population (σ) and sample (s) calculations. It works with large datasets entered as comma, space, or newline-separated values, and shows every step of the process.

The Formula

Mean (μ) = Σxᵢ / N
Variance (σ²) = Σ(xᵢ − μ)² / N
Std Dev (σ) = √Variance
Sample Std Dev (s) = √(Σ(xᵢ − x̄)² / (N−1))

FAQs

What is the difference between population and sample standard deviation?

Population standard deviation (σ) divides by N and is used when you have data for every member of the population. Sample standard deviation (s) divides by N−1 (Bessel's correction) and is used when you are working with a sample to estimate the population parameter.

What does a low vs. high standard deviation mean?

A low standard deviation means the data points are clustered closely around the mean, indicating low variability. A high standard deviation indicates the data is spread out over a wider range of values.