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Standard Deviation Calculator
Measure how spread out your numbers are, both population and sample standard deviation, computed in your browser.
HOW TO USE
- 1Type or paste your list of numbers. Separate values with commas, spaces, new lines or semicolons, any mix works, and negative or decimal values are fine.
- 2Results update live as you type: population and sample standard deviation, both variances, and the mean.
- 3Use the population result (σ) when your list is the entire group. Use the sample result (s) when your list is a sample of a larger group.
- 4Anything that is not a number is ignored, and a single value has no sample standard deviation, it is shown as N/A.
EXAMPLE
INPUT
2, 4, 4, 4, 5, 5, 7, 9
OUTPUT
σ 2 · s 2.1381 · mean 5
FAQ
What is the difference between population and sample standard deviation?
Population standard deviation (σ) divides by n and describes the entire group of values. Sample standard deviation (s) divides by n − 1 and estimates the spread of a larger group from your sample — it is always slightly larger.
What does standard deviation tell me?
It measures how far values typically sit from the mean. A small standard deviation means the numbers cluster close together; a large one means they are spread out.
How is the mean used?
Standard deviation is computed from the deviations of each value from the mean. The mean itself is shown alongside, since the same spread looks different around different centers.
Is my data sent anywhere?
No. All calculations run entirely in your browser, your numbers never leave your device.