Enter a data set to calculate mean, variance, and standard deviation. Toggle between sample (n−1) and population (n) formulas.
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Quick answers to common questions
Standard deviation measures how spread out numbers are from the mean. A low σ means values cluster near the average; a high σ means more spread.
Sample (n−1) is used when your data is a sample of a larger population. Population (n) is used when you have the complete data set.
Variance is the average of squared differences from the mean. Standard deviation is the square root of variance.
At least 2 numbers are required for standard deviation calculation.
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