Coefficient of Variation Calculator
The coefficient of variation (CV) is a standardized measure of relative variability expressed as a percentage. Unlike standard deviation, which is absolute and scale-dependent, CV allows you to compare the consistency of datasets with different units or magnitudes. This calculator computes the mean, standard deviation, variance, and coefficient of variation from your data. Lower CV indicates more consistency; higher CV indicates more variability relative to the mean. CV is essential in quality control, finance, and any field where comparing relative variability across different scales is important.
Coefficient of variation formula
CV = (Standard Deviation / Mean) * 100%
Also shows:
Variance = Standard Deviation^2
Standard Deviation = sqrt(variance)
CV interpretation guidelines
- CV < 15%: Low relative variability. Data is consistent and homogeneous.
- CV 15% to 30%: Moderate relative variability. Data shows some spread but is reasonably consistent.
- CV > 30%: High relative variability. Data is spread out and heterogeneous.
- Example: Two datasets both have standard deviation of 5. One has mean 20 (CV = 25%), the other has mean 100 (CV = 5%). The first is more variable relative to its mean.
Coefficient of variation: frequently asked questions
What is the coefficient of variation?
The coefficient of variation (CV) is the ratio of standard deviation to mean, expressed as a percentage: CV = (SD / Mean) * 100. It measures relative variability and allows comparison of datasets with different units or scales.
Why is CV useful when standard deviation alone is not?
Standard deviation depends on the scale of the data. A standard deviation of 10 is large for data with mean 5, but small for data with mean 1000. CV normalizes this by dividing by the mean, making it dimensionless and scale-independent.
How do I interpret the coefficient of variation?
Lower CV means less relative variability and more consistency. Higher CV means more relative variability. As a rule of thumb: CV < 15% is low variability, 15-30% is moderate, > 30% is high variability.
Can the coefficient of variation be negative?
No. CV is always positive because it uses the absolute value of the mean (or the mean is always positive). If your mean is negative, the calculation is the same, treating the mean as its absolute value.
When should I use CV instead of standard deviation?
Use CV when comparing variability across datasets with different means or units (e.g., comparing variability in prices of apples vs. cars). Use standard deviation when comparing variability within a single scale or unit.
Official sources
- NIST/SEMATECH e-Handbook of Statistical Methods: NIST Handbook.
- American Statistical Association: ASA.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.