Standard Deviation Calculator
Spread of a list of numbers, both ways.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
Standard Deviation Calculator
How to use this tool
- Enter your numbers, separated by commas, spaces or line breaks.
- Press Generate to see the mean and both standard deviations.
- Use Load sample for 2, 4, 4, 4, 5, 5, 7, 9, or Clear to start again.
Worked example
For 2, 4, 4, 4, 5, 5, 7, 9 the mean is 5, the population standard deviation is 2, and the sample standard deviation is about 2.138.
What this tool does not do / Limits
This tool treats the list exactly as entered. It does not remove outliers, weight values or test whether the data follows any distribution.
Frequently asked questions
Which result should I use?
Use the population result when the list is the whole group you care about, and the sample result when the list is a sample meant to stand for a larger group.
Why is the sample value larger?
The sample formula divides by one less than the count, which corrects for the fact that a sample tends to understate the spread of the larger group.
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