Standard Deviation Calculator
Calculate population and sample standard deviation, variance, and mean from a list of numbers.
Your result
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How to use this calculator
- Enter your values in the labeled fields, keeping the displayed units.
- Choose Calculate or press Enter in a single-line field.
- Review the result and the assumptions below before using it.
Formula and method
Population variance divides the sum of squared deviations from the mean by n. Sample variance divides by n−1. Standard deviation is the square root of variance.
Worked example
For 2, 4, 4, 4, 5, 5, 7, 9, the mean is 5, population variance is 4, and population standard deviation is 2.
What the result assumes
Up to 1,000 finite numbers are accepted. A sample standard deviation requires at least two observations.
Common question
Should I choose population or sample standard deviation?
Use population when your data covers the whole group of interest. Use sample when estimating variability in a larger population.