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Coefficient of Variation Calculator
Your numbers
Example: 10, 12, 23, 23, 16, 23, 21, 16 → mean 18, sample CV 29.10%, population CV 27.22%.
Behind the numbers
How the coefficient of variation is calculated
The sample CV uses the sample standard deviation (n-1), and the population CV uses the population SD (n) — the calculator shows both.
Example: 10, 12, 23, 23, 16, 23, 21, 16 — mean 18, sample SD 5.2372, so CV = 5.2372 ÷ 18 × 100 = 29.10%.
When should you use it?
- To compare the spread of two groups when their units or averages differ.
- To see risk per unit of return in an investment (a lower CV means more consistent returns).
- To check measurement variability in a lab or in quality control.
The CV is only meaningful when the mean is positive and not close to zero.
Good to know
FAQ
What is the coefficient of variation?
It measures relative variability: the standard deviation as a percentage of the mean. CV = (standard deviation ÷ mean) × 100.
What is a good coefficient of variation?
Lower means more consistent. As a rough guide, under 10% is low variability, 10–30% is moderate and above 30% is high — but what counts as good depends on the field.
What is the difference between sample and population CV?
Sample CV uses the sample standard deviation (divided by n−1) and population CV uses the population standard deviation (divided by n). This calculator shows both.
Can the coefficient of variation be over 100%?
Yes — when the standard deviation is bigger than the mean. It can also turn negative if the mean is negative, which is why the CV is only meaningful for a positive mean that is not close to zero.