Power BI adds calculated columns to fast Direct Lake data mode
Power BI's April 2026 update launches a preview for calculated columns and tables in Direct Lake mode. Direct Lake queries large datasets stored in OneLake without importing all the data first. These new columns compute values on the fly, avoiding extra storage or long refresh times. The columns can now pull user details, such as language preference or login name, using DAX functions. An updated NAMEOF function makes DAX code easier to read and maintain across reports. Both features need preview toggles in Power BI Desktop and work with OneLake tables.
Before, Direct Lake gave quick access to huge datasets but blocked calculated columns. You had to switch to slower Import mode for any custom math, piling on Power Query steps that dragged refreshes to hours on messy files. Now unmaterialized columns let you add those calculations directly, keeping Direct Lake speed for large data. This cuts through inherited report nightmares, paving a straight path to sub-second dashboard loads that match your source numbers exactly.
Analysis
This preview hands you the kill switch for four-hour refreshes on bloated queries – no more Excel cop-outs. Flip the Direct Lake calculated columns toggle in Power BI Desktop today, connect your largest dataset from OneLake, and build one YoY measure column to paste into your boss's next meeting dashboard.
Citation
This executive briefing was curated and analyzed by Collab365. To reference this analysis, please attribute: "This briefing is available on Collab365 Spaces (spaces.collab365.com)".