Quick answer
The coefficient of variation is CV = standard deviation ÷ |mean| × 100. A data set with mean 5 and standard deviation 2 has a CV of 40%.
Enter the data and choose population or sample. The calculator returns the CV, standard deviation and mean.
Related tools: Standard Deviation Calculator: Sample or population standard deviation with variance and mean. Z-Score Calculator: Standardize a value using a mean and standard deviation. Mean Median Mode Range Calculator: Mean, median, mode and range of a data set.
How to use the Coefficient of Variation Calculator
- Type data set, for example 4, 8, 15, 16, 23, 42.
- Choose data type: Sample (n − 1) and Population (n).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Data set | Text, such as 4, 8, 15, 16, 23, 42 | — |
| Data type | Choose one: Sample (n − 1); Population (n) | Starts at Sample (n − 1) |
Formula and method
Formula
CV = standard deviation ÷ |mean| × 100
IEEE-754 double precision; shown to at most 6 decimal places.
Ratio of dispersion to the mean, as a percentage.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Data set = 2, 4, 4, 4, 5, 5, 7, 9; Data type = Population (n).
| Result | Value |
|---|---|
| Coefficient of variation | 40 % |
| Standard deviation | 2 |
| Mean | 5 |
Example 2
Inputs: Data set = 10, 20, 30; Data type = Sample (n − 1).
| Result | Value |
|---|---|
| Coefficient of variation | 50 % |
| Standard deviation | 10 |
| Mean | 20 |
The first line is the headline result (coefficient of variation). Below it the coefficient of Variation Calculator lists standard deviation and mean, which describe the same case from other angles. IEEE-754 double precision; shown to at most 6 decimal places.
Comparing spread
CV expresses variability relative to the mean, so you can compare data on different scales: heights in cm and weights in kg. A CV of 40% is high; below 10% is quite consistent.
Cautions
CV is meaningless if the mean is near zero, and undefined at zero. It suits ratio-scale data (with a true zero) only; temperature in Celsius is not suitable. Choose population (n) or sample (n − 1) for the standard deviation.
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Data set: entering "-1, 1" shows "The mean is 0, so the coefficient of variation is undefined." beside that field and no result.
Choosing between the Coefficient of Variation Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Standard Deviation Calculator](/statistics/standard-deviation-calculator/) | data set and data type | Population standard deviation (σ) |
| [Z-Score Calculator](/statistics/z-score-calculator/) | value, mean and standard deviation | Z-score |
| [Mean Median Mode Range Calculator](/statistics/mean-median-mode-range-calculator/) | data set | Mean |
| [Median Calculator](/statistics/median-calculator/) | data set | Median |
| [Relative Standard Deviation Calculator](/statistics/relative-standard-deviation-calculator/) | data set and data type | Relative standard deviation |
Background: descriptive statistics
Population statistics divide by n and sample statistics divide by n − 1 (Bessel's correction), because a sample tends to understate variability. Use the population version when your data is every value in the group, and the sample version when it is a subset.
Defaults differ between tools, and so do quartile conventions, which can give slightly different values for small data sets; this page states the method it uses.
Assumptions and limitations
- Mean of 0 is undefined
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for data set to confirm this.
Frequently asked questions
What is a low CV?
Under about 15% is often considered low.
Is CV unitless?
Yes, it's a percentage.
What if the mean is negative?
The absolute value is used.
What does the Coefficient of Variation Calculator calculate?
Standard deviation relative to the mean. It returns Coefficient of variation, Standard deviation and Mean.
What formula does the Coefficient of Variation Calculator use?
CV = standard deviation ÷ |mean| × 100. Ratio of dispersion to the mean, as a percentage.
What do I need to enter in the coefficient of Variation Calculator?
You enter Data set and Data type.
How is the result rounded or limited?
IEEE-754 double precision; shown to at most 6 decimal places. Mean of 0 is undefined.
What does the “Data type” option change?
It sets how the coefficient of Variation is worked out. The choices are Sample (n − 1) and Population (n).
What is an example of a coefficient of Variation result?
With data set 2, 4, 4, 4, 5, 5, 7, 9 and data type Population (n), the coefficient of variation is 40 %.
Related calculators
- Standard Deviation Calculator — Sample or population standard deviation with variance and mean.
- Z-Score Calculator — Standardize a value using a mean and standard deviation.
- Mean Median Mode Range Calculator — Mean, median, mode and range of a data set.
- Median Calculator — Median of a data set.
- Relative Standard Deviation Calculator — Relative standard deviation (RSD) as a percentage.
- Variance Calculator — Sample or population variance.
- Sum of Squares Calculator — Sum of squared deviations from the mean, and sum of squared values.
- Midrange Calculator — Midpoint between the smallest and largest value.
- Outlier Calculator — Find outliers with Tukey's 1.5 × IQR fences.
Sources
- Standard statistics definition (e.g. NIST/SEMATECH e-Handbook of Statistical Methods)
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.