Math
Standard Deviation Calculator
Enter a data set to calculate mean, variance, and standard deviation. Toggle between sample (n−1) and population (n) formulas.
4.8
Mean
4.8444
Variance
2.201
Std Deviation
10
Count (n)
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Frequently Asked Questions
Quick answers to common questions
What is standard deviation?+
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 vs population standard deviation?+
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.
What is variance?+
Variance is the average of squared differences from the mean. Standard deviation is the square root of variance.
How many data points do I need?+
At least 2 numbers are required for standard deviation calculation.