P-Value
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Statistics — Relative Spread
Coefficient of Variation Calculator
Paste your data to get the coefficient of variation — the standard deviation as a percentage of the mean.
Coefficient of variation
—
Sample standard deviation ÷ mean.
| Count n | — |
|---|---|
| Mean | — |
| Sample std. deviation | — |
| Population std. deviation | — |
| Population CV | — |
Show our math
Enter your figures above to see the step-by-step working.
Only meaningful for ratio data with a positive meanEverything computed client-side — nothing leaves this page
How the Coefficient of Variation Calculator Works
The coefficient of variation (CV) expresses the standard deviation as a percentage of the mean, so you can compare the relative variability of data sets that have different units or very different averages. A CV of 15% means the standard deviation is 15 percent of the mean.
Because it divides by the mean, the CV is only meaningful for data measured on a ratio scale with a positive mean — it is not useful when the mean is near zero or when values can be negative. The calculator reports both the sample and population versions.
CV = standard deviation ÷ mean × 100%
Frequently Asked Questions
What is a good coefficient of variation?
It depends on the field. A lower CV means less relative variability. In many contexts a CV under about 15 percent is considered low variability and over 30 percent is high, but there is no universal cut-off — compare like with like.
Why use CV instead of standard deviation?
Standard deviation is in the same units as the data, so you cannot fairly compare the spread of, say, heights in centimetres with weights in kilograms. The CV is unitless, which lets you compare variability across different scales.
When should I not use the coefficient of variation?
Avoid it when the mean is zero or close to it (the CV explodes), when data can be negative, or when the data is on an interval rather than ratio scale, such as temperatures in Celsius.
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