Coefficient of variation calculator
Useful for comparing the stability of two prices or the precision of two instruments whose averages differ.
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How to use it
- Enter data (separate numbers with commas, spaces or new lines) and data type.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
CV = (standard deviation ÷ |mean|) × 100%.
Example
Inputs: Data type = Sample (divide by n - 1). Result: Coefficient of variation (CV): 42.7618%; Standard deviation: 2.13809; Mean: 5.
Limits and caveats
- Meaningful only for positive ratio-scale data, such as weights and prices, not Celsius temperatures.
- It becomes unstable as the mean approaches zero.
Questions about this tool
What counts as a low CV?
It depends on the field. In labs under 10% often signals good precision, while 30% can be normal for sales.
Why not compare standard deviations directly?
A spread of 5 is large for an item priced 10 and tiny for one priced 1,000. CV expresses the spread relative to the mean.
Is it the same as relative standard deviation?
Yes, analytical chemistry calls it RSD, relative standard deviation.