SHAPES, DATA, AND SCHOOL MATH
Standard Deviation Calculator
Calculate mean, variance, and standard deviation from comma-separated data using either population or sample rules.
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Enter your values and select Calculate. Your result stays on this device.
How it works
Standard deviation is the square root of the mean squared deviation; sample variance divides by n − 1.
Assumptions
Values are unweighted. Choose population or sample based on how the data was collected.
About this calculator
This standard deviation calculator keeps the population-versus-sample choice explicit. It returns the mean and variance alongside the standard deviation so students can check each stage.
How to use it
- Paste the comma-separated values.
- Choose population when the list is the full group or sample when it represents a larger group.
- Calculate the standard deviation and variance.
- Compare the result with your course convention and rounding rules.
Use case
standard deviation calculator: a clear planning check
Enter a comma-separated data set and compare standard deviation, variance, mean, count, and the selected n or n − 1 method.
Calculate spread for a data set while explicitly choosing the sample or population convention.
Method and update
Last reviewed: 2026-08-22. This tool performs the stated formula locally in your browser using the values you enter.
Frequently asked questions
What is standard deviation?
It measures how far values typically spread from the mean.
When should I use sample standard deviation?
Use the sample form when the observations are a sample used to estimate variation in a larger population.
Why does sample standard deviation use n minus 1?
The n − 1 divisor is the conventional correction used when estimating population variance from a sample.
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