How to Use AVERAGEX in DAX in Power BI: Syntax and Examples

Use AVERAGEX in DAX to calculate the average of an expression evaluated over a table. It takes two arguments: a table and an expression to evaluate for each row, then returns the average of those results.

Syntax

The AVERAGEX function requires two parts:

• Table: The set of rows to evaluate.
• Expression: The calculation done on each row.

It returns the average of the expression results across the table.

DAX

AVERAGEX(<Table>, <Expression>)

Example

This example calculates the average sales amount per product from a table named Sales with columns Product and SalesAmount.

DAX

Average Sales = AVERAGEX(Sales, Sales[SalesAmount])

Output

If Sales table has SalesAmount values: 100, 200, 300, the result is 200

Common Pitfalls

Common mistakes include:

• Using AVERAGEX without a proper table argument, which causes errors.
• Confusing AVERAGEX with AVERAGE, which only works on a single column.
• Writing expressions that return non-numeric values, causing calculation errors.

Always ensure the expression returns numbers and the table is correctly filtered if needed.

DAX

/* Wrong: Using a column instead of a table */
Average Wrong = AVERAGEX(Sales[SalesAmount], Sales[SalesAmount])

/* Correct: Use the whole table */
Average Correct = AVERAGEX(Sales, Sales[SalesAmount])

Quick Reference

Argument	Description
Table	The table to iterate over.
Expression	The calculation to perform on each row.
Return	Average of the expression results as a number.

Key Takeaways

AVERAGEX calculates the average of an expression evaluated row by row over a table.

Always provide a table as the first argument and a numeric expression as the second.

Do not confuse AVERAGEX with AVERAGE; AVERAGE works on a single column only.

Ensure your expression returns numbers to avoid errors.

Use AVERAGEX to perform averages on calculated or filtered data, not just raw columns.