Coefficient of Variation Calculator
Compare variability between data sets with different units or scales, using the coefficient of variation.
About the Coefficient of Variation Calculator
Paste your data and choose whether it's a sample or the whole population. The calculator gives the coefficient of variation, the mean and the standard deviation.
The coefficient of variation (CV) is the standard deviation as a percentage of the mean. Because it has no units, you can compare the spread of, say, house prices in two cities or the consistency of two machines.
The formula
CV = (standard deviation ÷ |mean|) × 100%
Worked example
Five readings: 12, 15, 11, 14, 13 (a sample)
- Mean: 13
- Sample standard deviation: 1.581
- CV = 1.581 ÷ 13 = 12.16%
Questions people ask
What's a good CV?
Lower means more consistent. In lab assays under 10% is often considered good; it depends on the field.
Can I use it with negative data?
Only with ratio data on a true zero scale (weights, prices). It's misleading for temperatures in °C.
Sample or population?
Sample if your data is part of a bigger group, which is usual; population only if you measured every member.