In statistics, **deciles** are numbers that split a dataset into ten groups of equal frequency.

The first decile is the point where 10% of all data values lie below it. The second decile is the point where 20% of all data values lie below it, and so forth.

We can use the following function to calculate the deciles for a dataset in Excel:

=PERCENTILE(CELL RANGE, PERCENTILE)

The following example shows how to use this function in practice.

**Example: Calculate Deciles in Excel**

Suppose we have the following dataset with 20 values:

The following image shows how to calculate the deciles for the dataset:

The way to interpret the deciles is as follows:

- 20% of all data values lie below
**67.8**. - 30% of all data values lie below
**76.5**. - 40% of all data values lie below
**83.6**.

And so on.

To place each data value into a decile, we can use the **PERCENTRANK.EXC()** function, which uses the following syntax:

=PERCENTRANK.EXC(CELL RANGE, DATA VALUE, SIGNIFICANCE)

The following image shows how to use this function for our dataset:

Note that this function finds the relative rank of a value in a dataset as a percentage and rounds to one digit, which is equivalent to finding the decile that the value falls in.

The way to interpret the output is as follows:

- The data value 58 falls between the percentile 0 and 0.1, thus it falls in the first decile.
- The data value 64 falls between the percentile 0.1 and 0.2, thus it falls in the second decile.
- The data value 67 falls between the percentile 0.1 and 0.2, thus it falls in the second decile.
- The data value 68 falls between the percentile 0.2 and 0.3, thus it falls in the third decile.

And so on.

**Additional Resources**

How to Calculate a Five Number Summary in Excel

How to Normalize Data in Excel

How to Easily Find Outliers in Excel