How this calculation works
Variance measures spread by averaging squared distances from the mean. Unlike standard deviation, its unit is squared: measurements in metres produce variance in square metres. Use this tool when a statistical formula needs variance directly; the companion deviation result restores the original unit.
Worked example
This example uses illustrative inputs. Your current result is shown above.
For 2, 4, 4, 4, 5, 5, 7 and 9, x̄ = 5 and squared deviations total 32. In population mode, variance = 32 ÷ 8 = 4, and the associated standard deviation is 2.
Assumptions and limits
- Use population mode for a complete group and sample mode for an estimate from sampled observations.
- Sample variance requires at least two values.
- Variance cannot be negative. A zero result means all entered observations are identical.
Questions people ask
Why is variance not in the original unit?
Each deviation is squared before averaging. Squaring prevents positive and negative deviations from cancelling but also squares the measurement unit.
Can I compare variance across different units?
Not directly. Changing metres to centimetres multiplies each measurement by 100 and the variance by 10,000. Convert to a common unit before comparing.