# How to Winsorize Data in Excel

To winsorize data means to set extreme outliers equal to a specified percentile of the data.

For example, a 90% winsorization sets all observations greater than the 95th percentile equal to the value at the 95th percentile and all observations less than the 5th percentile equal to the value at the 5th percentile.

This tutorial provides a step-by-step example of how to winsorize a dataset in Excel.

### Step 1: Create the Data

First, we’ll create the following dataset:

### Step 2: Calculate the Upper and Lower Percentiles

For this example, we’ll perform a 90% winsorization. This means we’ll set all values greater than the 95th percentile equal to the 95th percentile and all values less than the 5th percentile equal to the 5th percentile.

The following formulas show how to find the 5th and 95th percentiles:

The 5th percentile turns out to be 12.35 and the 95th percentile turns out to be 92.05.

### Step 3: Winsorize the Data

Lastly, we’ll use the following formula to winsorize the data:

Note that we just copy and pasted the formula in cell F2 down to the remaining cells in column F.

In this case, the value 3 became changed to 12.35 and the value 98 became changed to 92.05.

Note that in this example we performed a 90% winsorization, but it’s possible to also perform an 80% winsorization, 95% winsorization, 99% winsorization, etc. by simply calculating different upper and lower percentiles.

## 3 Replies to “How to Winsorize Data in Excel”

1. leon says:

a shame then that excel’s percentile calculation is not robust.
try a sequence of integers 1 to 10 and ask for the 25th percentile. one might expect to see 2.5?
try a sequence integers 1 to 100, ask for the 25th percentile. one might expect it to be 10* that of the 1-10 dataset? or perhaps 25?

2. Dveredokomory says:

Thank you!

3. Thomas says:

Why don’t you use Power Query tool in Excell?