In statistics, **quartiles **are values that split up a dataset into four equal parts.

When analyzing a distribution, we’re typically interested in the following quartiles:

- First Quartile (
**Q1**): The value located at the 25th percentile - Second Quartile (
**Q2**): The value located at the 50th percentile - Third Quartile (
**Q3**): The value located at the 75th percentile

You can use the following syntax in DAX to calculate quartiles for specific column in a table:

**Q1 = PERCENTILE.INC(table_name[column_name], 0.25)
Q2 = PERCENTILE.INC(table_name[column_name], 0.5)
Q3 = PERCENTILE.INC(table_name[column_name], 0.75)
**

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

**Example: How to Calculate Quartiles in Power BI**

Suppose we have the following table named **my_data** in Power BI that contains information about various basketball players:** **

Suppose that we would like to calculate the quartiles for the **Points** column.

To calculate the first quartile, click the **Table tools** tab and then click the **New measure** icon:

Then type the following formula into the formula bar:

**Q1 Points = PERCENTILE.INC(my_data[Points], 0.25)**

This will create a new measure that contains the value of the 1st quartile of the **Points** column:

Next, repeat this process to create a measure for the 2nd and 3rd quartiles as well by replacing the **0.25** in the formula with **0.5** and **0.75,** respectively.

If you’d like to view the values for the quartiles, insert card visualizations into a Report View:

From the output we can see:

- The first quartile is located at
**14.25**. - The second quartile is located at
**19**. - The third quartile is located at
**22**.

By knowing only these three values, we have a good understanding of the distribution of values in the **Points **column.

**Note**: You can find the complete documentation for the **PERCENTILE.INC** function in DAX here.

**Additional Resources**

The following tutorials explain how to perform other common tasks in Power BI:

Power BI: How to Calculate Percent of Total by Category

Power BI: How to Calculate Percent Change

Power BI: How to Calculate Median