Standard Deviation Calculator
Enter a list of numbers separated by commas or spaces to calculate the standard deviation and variance.
Last updated: August 30, 2026
Frequently asked questions
What's the standard deviation of 4, 8, 15, 16, 23, 42?
About 13.49 using the sample formula (dividing by n−1), or 12.32 using the population formula (dividing by n) - the mean of this set is 18.
When should I use sample vs. population standard deviation?
Use population standard deviation when your numbers represent the entire group you care about; use sample standard deviation when your numbers are a subset used to estimate a larger population's spread.
What does a low vs. high standard deviation mean?
A low standard deviation means the values cluster tightly around the mean, while a high standard deviation means they're spread out widely - it's a measure of consistency, not of the average itself.
What does it mean if the standard deviation is zero?
A standard deviation of zero means every value in the data set is identical - there's no spread or variation at all. Any variation among the numbers, even a small one, produces a standard deviation greater than zero.
Where do I find standard deviation on a calculator?
You don't need a special scientific calculator function - enter your list of numbers above (separated by commas or spaces) and this calculator computes the standard deviation directly, along with the variance and mean.