# Skewness in Excel (SKEW)

## Skew Excel Function

In Excel, **skewness** can be comfortably calculated using the **SKEW Excel function**. The only argument needed for SKEW function is the range of cells containing the data.

For example the function:

SKEW(B3:B102)

will calculate skewness for the set of values contained in cells B3 through B102.

## Calculating Sample Skewness in Excel

The built-in **SKEW Excel function** calculates **sample skewness**:

Here you can see a detailed derivation and explanation of skewness formula.

## Calculating Population Skewness in Excel

Unlike with variance or standard deviation (which you can calculate for either sample or population in Excel), there is **no direct built-in Excel function for population skewness**. You can either calculate is directly…

… or by **adjusting the SKEW Excel function** (this option usually leads to smaller Excel file size and better performance, as you don’t need to calculate the individual deviations from the mean in extra cells).

## Adjusting from Sample to Population Skewness in Excel

SKEW(Data!$B$16:$B$10015)/SQRT($G$5*($G$5-1))*($G$5-2)

This is the function I use in the Summary Statistics Spreadsheet. The first part – SKEW(Data!$B$16:$B$10015) – is the built-in Excel SKEW function for sample skewness of cells B16 through B10015, and the rest is the **adjustment from sample to population skewness**, where cell G5 calculates population size:

G5 = COUNT(Data!$B$16:$B$10015).

The whole formula is:

**Population Skewness = Sample Skewness x (N-2) / Square root of (N x (N-1))**

Where N = population size (number of values)

You can see how skewness Excel calculation works in practice in the Summary Statistics Calculator.