Standard Deviation Calculator
Calculate mean, variance, and standard deviation for a data set, population or sample.
Standard deviation
—
About this tool
Paste a set of numbers to get the standard deviation along with the mean, variance, count, sum, range, and the mean absolute deviation. Choose "sample" when your data is a subset drawn from a larger group (this divides by n − 1, Bessel's correction) or "population" when it's the entire group (divides by n). Every step is computed in your browser.
Frequently asked questions
- Sample or population — which do I pick?
- If you measured every member of the group you care about, use population. If you measured a sample and want to estimate the wider group's spread, use sample. When unsure, sample is the safer default and the one most statistics courses expect.
- How is variance related to standard deviation?
- Variance is the average of the squared differences from the mean; standard deviation is its square root, which puts the spread back into the original units.
- What counts as a valid number?
- Integers and decimals, negative or positive, plus scientific notation like
1.2e3. Anything that can't be parsed is listed in the hint and skipped.