This blog post is Human-Centered Content: Written by humans for humans.

As a Tableau Consultant or Data Analyst, many of us may find ourselves looking at the blank canvas of our first Power BI report, trying to understand the terminology of this new tool that many of us may find ourselves switching to or adding to our skills repertoire. If you are trying to learn the desktop environment for the first time, consider checking out my prior blog here. If you want to create your first report and familiarize yourself with a basic overview of this process, check out this blog from my colleague Robby.

However, in this blog, I will specifically be diving into what calculated columns and measures mean in Power BI, and how these terms differ from related concepts in Tableau.

The Comparison

While I will delve into the particulars of each, Calculated Fields in Tableau are conceptually similar to Calculated Columns in Power BI. On the other hand, the concept of Table Calculations are the rough equivalent of Power BI Measures.

To begin, a calculated column refers to creating a new field in the data model by adding row-level data. While the use cases are endless, some basic examples might include:

• Concatenating or Cleaning Strings.
• Performing row level math such as:
  Profit = Sales[Revenue] – Sales{UnitCost]
  Sales = Sales[Quantity] * Sales[UnitPrice]
• Adding new groups to filter or slice data is visuals.

Since each row is evaluated individually, the calculated columns are part of the row context. Although there are obvious pros, some cons might include slightly less performant queries in large datasets since the model size is growing, which will in turn increase refresh time as this column is pre-calculated and stored with the original data in the model.

On the other hand, Power BI Measures are formula-driven calculations on aggregated data and return a singular value or result for the current context. These are useful when you want calculations to compute after users might select filters or slicers. As these are dynamic, measures are useful for aggregations or KPIs such as:

TotalSales = SUM(OrderSales[OrderTotal])

As mentioned, the measures are calculated at the filter context of the visual/report, and they are computed on the fly as they are not stored anywhere in the base data model. Although they compute at the time of query, not having to save a value for each row in the data will save storage space and costs.

Here’s a helpful chart of some of the key differences between calculated columns and measures:

In summary, understanding the differences and when to use calculated columns vs. measures is key to building efficient Power BI Reports. And if you have questions about building your Power BI Reports, feel free to drop us a line on the banner below!