Math
Use OmniCalc's standard deviation calculator to measure how spread out a list of numbers is with either sample or population mode.
Standard deviation calculator
Paste a list of numbers, then switch between population and sample standard deviation to summarize variation without doing the formula manually.
Why this result matters
A practical descriptive-statistics entry page that helps open the broader approved stats cluster. Use the tool above to enter a few clear inputs and get a practical answer you can use right away.
This standard deviation calculator helps students, analysts, and everyday users summarize variation in a data set quickly. Paste your numbers, choose sample or population mode, and see the mean, variance, range, and standard deviation in one place.
Formula and method
The calculator finds the mean, measures each value's squared distance from that mean, divides by either n or n minus 1, and then takes the square root to get standard deviation.
Example
For 2, 4, 4, 4, 5, 5, 7, 9, the population standard deviation is 2.
FAQ
Short answers to the questions people often ask before or after using the tool.
Question
Population standard deviation uses the full data set and divides by the total count. Sample standard deviation uses a sample from a larger group and divides by count minus one.
Question
It means the values are more spread out from the mean, so the data varies more.
Question
Enter numbers separated by commas or line breaks. The calculator ignores any non-numeric entries.
Next stats calculator
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Math
Use OmniCalc's confidence interval calculator to estimate a plausible range around a sample mean using a chosen confidence level.