Different sum calculated by dax and power query - why?

Hi jaryszek ,

Thanks for reaching out to the Microsoft fabric community forum.

 

I have reproduced this scenario in Power BI (Fabric) to investigate why Power Query and DAX were showing different totals initially. I loaded the dataset containing the CostInBillingCurrency column into Power BI. In Power Query, I created a Blank Query, opened Advanced Editor, and used the formula:

= List.Sum(Costs[CostInBillingCurrency])

 

After applying the changes, I brought that result into the data model.

 

I also created a DAX measure using:

Total Amortized Cost = SUM(Costs[CostInBillingCurrency])

 

Then, I added both values to a visual to compare them. The totals now match. This shows that when both queries and models reference the same clean data, Power Query’s List.Sum and DAX’s SUM() produce the same results.

It’s likely that any earlier mismatch was caused by intermediate steps, filters, or transformations applied before running the List.Sum. After running this setup clearly, the results are consistent between Power Query and DAX.

Posting this here to help anyone facing the same kind of confusion between Power Query and DAX totals in Power BI (Fabric).

 

Please find the attached pbix file for your reference.

 

If the response has addressed your query, please Accept it as a solution and give a 'Kudos' so other members can easily find it.

Best Regards,
Tejaswi.
Community Support