Coefficient of Variation Calculator
Spread expressed as a percentage of the mean, so you can compare how variable two datasets are even when they're on totally different scales.
From a list of values
Already have the mean and standard deviation?
How it works
The coefficient of variation is simply the standard deviation divided by the mean, then multiplied by 100 to read as a percent. It answers 'how big is the spread compared to the average size of the numbers?'
Because it's a ratio, it strips away the units. That lets you compare the variability of things measured on wildly different scales — say the consistency of monthly rainfall against the consistency of test scores — on equal footing.
Paste a list and the tool works out the mean and sample standard deviation before dividing. Or drop straight to the second box: a standard deviation of 8 against a mean of 50 gives a CV of 8 ÷ 50 × 100 = 16%.
Frequently asked questions
What makes the CV more useful than the standard deviation alone?
Standard deviation carries units and scale, so a spread of 10 means something different for salaries than for shoe sizes. The coefficient of variation reports spread relative to the mean, which lets you compare datasets that would otherwise be apples and oranges.
What counts as a high coefficient of variation?
There's no universal cutoff — it depends on the field. Broadly, a CV under about 10% suggests low variability, while values well above 30% point to a lot of scatter. Always judge it against what's normal for your kind of data.
Why does the calculator refuse a mean of zero?
The CV divides by the mean, and dividing by zero has no answer. It also loses meaning when the mean is near zero, since the ratio explodes. So the tool shows a dash unless the mean is a real, non-zero number.
Can I use it with negative data?
It's best kept to data that's all positive. When values straddle zero the mean can be tiny or negative, which makes the ratio unstable or hard to interpret. The coefficient of variation is most meaningful for positive measurements like time, weight, or price.