σ Statistics Calculator

Standard Deviation Calculator

Calculate population and sample standard deviation, variance, mean, coefficient of variation, and a complete statistical summary — with step-by-step working shown for each value.

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Both population (σ) and sample (s) standard deviations shown.

Frequently Asked Questions

Population vs Sample standard deviation?
Use population σ when you have ALL data points of the group. Use sample s when you have a subset and want to estimate the population SD. Sample uses n−1 (Bessel's correction) instead of n in the denominator.
What is the coefficient of variation (CV)?
CV = (σ ÷ mean) × 100%. It expresses the standard deviation as a percentage of the mean, allowing comparison of variability between datasets with different units or magnitudes.