Coefficient of Variation Calculator
Find relative variability as a percentage.
How the coefficient of variation works
The coefficient of variation (CV) expresses variability relative to the mean, as a percentage — a scale-free measure that lets you compare spread across datasets with different units or very different magnitudes, where comparing raw standard deviations wouldn't be meaningful.
Enter the mean and standard deviation of your dataset. The calculator returns the CV as a percentage.
CV is most meaningful for data measured on a ratio scale with a meaningful, non-zero mean (e.g. weights, prices, durations) — it is not meaningful for data that can be zero or negative in a way that makes the mean an unstable reference point.
The formula
CV = Standard deviation ÷ |Mean| × 100
Divide the standard deviation by the absolute value of the mean, then multiply by 100 to express it as a percentage.
Worked example
Mean of 50, standard deviation of 10
10 ÷ 50 × 100 = 20% coefficient of variation.
Frequently asked questions
What counts as a "high" CV?
It depends heavily on the field and what's being measured — there's no universal threshold. Comparing CV across similar datasets or over time is more useful than judging a single value in isolation.
Why can't the mean be zero?
CV divides by the mean, so a mean of zero makes the ratio undefined — this typically signals CV isn't a meaningful measure for that particular dataset.
When is CV more useful than comparing standard deviations directly?
When comparing variability across datasets with different units or very different scales — for example, comparing the relative spread of salaries (in thousands) against ages (in years) only makes sense in relative (CV) terms.
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