Why should calculated columns be used carefully?

< 1 min read

Calculated columns should be used carefully because they increase model size and memory usage.
In one project, adding multiple calculated columns on a large fact table slowed report refresh.
Each row stores the calculated value, unlike measures that compute on demand.
High-cardinality columns like transaction IDs consume significant memory.
They also increase storage in Power BI Service, affecting performance.
Using measures instead of calculated columns reduces data duplication.
If a column can be computed in Power Query or at source, it is more efficient.
So unnecessary calculated columns can degrade both refresh and query performance.

Power BI Essentials