Standard Deviation Calculator
Paste a list of numbers to get the standard deviation, variance, and mean — choose sample (n−1) or population (n) — instantly, in your browser.
Paste a list of numbers to get the standard deviation, variance, mean and count, for a sample or a whole population. It runs in your browser.
How to use it
- Paste your numbers, separated by commas, spaces or new lines.
- Choose sample or population.
- Read the standard deviation, variance, mean and count.
Example
For 2, 4, 4, 4, 5, 5, 7, 9 the mean is 5. As a population the standard deviation is exactly 2 (variance 4). As a sample it is 2.138 (variance 4.571). Five test scores, 72, 85, 90, 64 and 79, give a mean of 78 and a sample standard deviation of 10.32.
Sample or population?
Use population when your numbers are every value in the group, and sample when they are a subset used to estimate a larger group. The sample version divides by n − 1, so it needs at least two numbers; with one number the tool asks you to add data or switch to population.
Good to know
A small value means the numbers are close to the mean. In roughly bell-shaped data, about 68% of values lie within one standard deviation and 95% within two. Read sample vs population and the step-by-step guide.
FAQs
Can standard deviation be negative?
No. It is a square root, so it is zero or positive, and zero only when every value is the same.
What units does it use?
The same units as your data. The variance is in squared units.