How to use the Coefficient of Variation Calculator
Paste your numbers separated by commas, spaces or new lines. The calculator finds the mean and standard deviation, then shows the standard deviation as a percentage of the mean.
Why use it instead of the standard deviation
The standard deviation is in the same units as your data, so it is hard to compare across scales. A spread of 5 kg means a lot for cats and very little for cars. The coefficient of variation turns the spread into a percentage of the average, so you can compare how consistent two very different things are.
Worked example
Two machines fill bags. Machine A averages 500 g with a standard deviation of 10 g, so its CV is 2%. Machine B averages 50 g with a standard deviation of 3 g, a CV of 6%. Machine A has the bigger spread in grams but is three times more consistent relative to what it fills.
The formula
CV = standard deviation ÷ mean × 100
Examples
- 2, 4, 6, 8, 10
Coefficient of variation: 47.14045208%
- Stable values 98, 100, 101, 99, 102
Coefficient of variation: 1.41421356%
- Volatile values 20, 80, 35, 120, 60
Coefficient of variation: 55.80443121%
Limitations and assumptions
Only meaningful for data on a ratio scale with a positive mean, such as weights, prices or times. It breaks down when the mean is close to zero.
Frequently asked questions
What is the formula?
Standard deviation ÷ mean × 100.
When is it useful?
Comparing variability between data sets with different units or averages.
When does it fail?
It breaks down when the mean is near zero.
Population or sample?
This tool uses the population standard deviation.