The coefficient of variation (CV) answers a question standard deviation alone can't: is this data set more or less variable relative to its own average? By expressing spread as a percentage of the mean, CV lets you compare consistency across data sets measured in different units, on different scales, or with very different typical values.
How the Coefficient of Variation Calculator works
The calculator applies CV = SD / mean × 100. When you enter a raw data set, it first computes the mean and either the sample standard deviation (dividing squared deviations by n − 1) or the population standard deviation (dividing by n), depending on which you select. That SD is then divided by the mean and multiplied by 100 to produce the CV percentage. When you already know the mean and SD, the From Mean & SD tab skips straight to that final division.
Inputs and what they mean
On the CV tab, paste any list of numeric values separated by commas, spaces, semicolons, or new lines — non-numeric entries are automatically skipped and reported. Choose Sample SD when your data is a sample used to estimate a larger population (the more common case), and Population SD when your data represents the entire population you care about. On the From Mean & SD tab, enter the mean and standard deviation directly if you've already calculated or been given them — for example from a lab report or a summary statistics table.
Limits and edge cases
CV is undefined when the mean is zero. CV is intended primarily for positive ratio-scale data; signed data can make the ratio unstable — the calculator flags this instead of showing a misleading number. CV also becomes less informative for data measured on an interval scale (like temperature in Celsius, where zero is arbitrary) rather than a true ratio scale (like weight, price, or count). And because CV is a ratio, a data set with a very small mean can produce an extremely large CV even when its absolute spread is modest — always look at the mean and SD alongside the CV, not the CV in isolation.