You can use the following syntax in DAX to create a new column that displays the percent of a column total:
Percent of Total = 'my_data'[Points] / SUM('my_data'[Points])
This particular example creates a new column named Percent of Total that displays the percent of the total of the Points column that a given row represents.
The following example shows how to use this syntax in practice.
Example: How to Calculate Percent of Total in Power BI
Suppose we have the following table in Power BI named my_data that contains information about points scored by basketball players on various teams:
Suppose we would like to add a new column that shows how much each individual value in the Points column represents as a percentage of the total values in the Points column.
To do so, click the Table tools tab along the top ribbon, then click the New column icon:
Then type in the following formula into the formula bar:
Percent of Total = 'my_data'[Points] / SUM('my_data'[Points])
This will create a new column named Percent of Total that shows how much each individual value in the Points column represents as a percentage of the total values in the Points column:
If we add up all of the values in the Points column, we’ll find that the total is 256.
Thus, we can see from the Percent of Total column:
- The first player accounts for 22/256 = .0859 or 8.59% of total points.
- The second player accounts for 14/256 = .0546 or 5.46% of total points.
- The third player accounts for 19/256 = .0742 or 7.42% of total points.
And so on.
If you’d like to display the values as percentages, then click the dropdown arrow next to Format and then click Percentage:
Each of the values in the Percent of Total column will now be displayed as percentages:
Additional Resources
The following tutorials explain how to perform other common tasks in Power BI:
How to Count Number of Occurrences in Power BI
How to Use “If Contains” in Power BI
How to Write an IF Statement in Power BI
