Coefficient of Variation Calculator
Calculate the coefficient of variation (CV) from raw data or from a mean and standard deviation. The CV expresses relative variability as a percentage, so you can compare spread across different scales.
- Mean (x̄)
- 19.57
- Std. deviation
- 5.44
Distribution
CV = 27.81%How to use this calculator
- Choose “Raw data” to paste your numbers, or “Mean & SD” to enter summary statistics directly.
- For raw data, pick whether it is a sample or a whole population.
- Read the coefficient of variation as a percentage, along with the mean and standard deviation used.
What is the coefficient of variation?
The coefficient of variation (CV), also called the relative standard deviation, measures how large the standard deviation is relative to the mean. Because it is a ratio, it has no units and is usually expressed as a percentage — which makes it ideal for comparing the variability of data sets measured on different scales or in different units.
Coefficient of variation formula
The CV is the standard deviation divided by the mean, times 100%:
Use the sample standard deviation (s) and sample mean (x̄) for sample data, or the population values (σ and μ) for a whole population.
How to interpret the coefficient of variation
A higher CV means more relative variability; a lower CV means the data is more consistent relative to its mean. As a rough guide, a CV under about 10% is often considered low variability, 10–30% moderate, and above 30% high — but sensible thresholds depend entirely on the field and context.
The CV is only meaningful for data measured on a ratio scale with a true zero and a positive mean. It is not appropriate when the mean is zero or when values can be negative.Coefficient of variation in Excel
There is no single CV function in Excel, so combine two functions: =STDEV.S(range)/AVERAGE(range) for a sample, or =STDEV.P(range)/AVERAGE(range) for a population. Multiply by 100 and format as a percentage to get the %CV.
Frequently asked questions
What is a good coefficient of variation?
It depends on the field, but as a rough rule of thumb a CV below 10% indicates low variability, 10–30% moderate variability, and above 30% high variability. Always interpret it in the context of your data.
Why use the coefficient of variation instead of the standard deviation?
The standard deviation is in the same units as the data, so you cannot directly compare the spread of data sets measured on different scales. The coefficient of variation is unitless, which lets you compare relative variability across different measurements.
Can the coefficient of variation be negative?
The standard deviation is always positive, so the CV is negative only if the mean is negative. Because of this, the CV is normally used only for data with a positive mean, and is undefined when the mean is zero.
How do I calculate the coefficient of variation in Excel?
Divide the standard deviation by the mean: =STDEV.S(range)/AVERAGE(range) for a sample, then format the result as a percentage.