# How to calculate the coefficient of variation in Excel

Divide the standard deviation by the mean and format as a percentage: `=STDEV.S(B2:B7)/AVERAGE(B2:B7)`.

**Excel:** `=STDEV.S(B2:B7)/AVERAGE(B2:B7)` (Excel 2010 and later)

**Google Sheets:** the same formula works.

## Example

Sample data (row 1 is the header):

| A | B | C | D |
| --- | --- | --- | --- |
| Week | Units sold |  | Coefficient of variation |
| W1 | 120 |  |  |
| W2 | 135 |  |  |
| W3 | 110 |  |  |
| W4 | 150 |  |  |
| W5 | 125 |  |  |
| W6 | 140 |  |  |

Formula in E1: `=STDEV.S(B2:B7)/AVERAGE(B2:B7)`

Result: 11.1%

## How it works

The standard deviation (about 14.5 units) only means something next to the size of the numbers. Dividing by the mean (130) turns it into a relative spread: 11.1%. That lets you compare how steady two products are even when one sells ten times more.

## Other ways

- `=STDEV.P(B2:B7)/AVERAGE(B2:B7)`: Use the population standard deviation when the weeks are all the data there is. (Slightly lower: 10.2%.)

## Common mistakes

- The coefficient of variation is meaningless when the mean is near zero or the data has negative values, like temperatures in Celsius.
- Format the cell as a percentage; otherwise it shows 0.11.

## Questions

**Is there a CV function in Excel?**

No; the formula above is the standard way.

**What counts as a high CV?**

It depends on the field, but under 10% is usually considered steady and over 30% quite variable.

Every formula and result on this page was checked by running it in the Spreadsheet Practice formula engine on 2026-10-30.

Source: https://spreadsheetpractice.com/formulas/coefficient-of-variation