Find mean, variance and standard deviation of a data set.
Calculated locally in your browser.
Understanding your result
Use sample SD when your data is a sample of a larger group, and population SD when it is the whole group.
Formula and method
Variance is the average of squared deviations from the mean; standard deviation is its square root. Sample SD divides by n − 1, population SD by n.
Worked example
For 2, 4, 4, 4, 5, 5, 7, 9 the mean is 5 and the population standard deviation is 2.
How to use this tool
- Enter your numbers, separated by commas, spaces or new lines.
- Read the statistics.
Common mistakes to avoid
- Confusing sample and population standard deviation.
About the Standard Deviation Calculator
Compute the mean, variance and both population and sample standard deviation for a list of numbers.
Frequently asked questions
Sample or population SD?
Use sample SD (n − 1) for a sample, and population SD (n) when you have the entire population.