DAX user-defined functions (UDFs)

Concept

DAX user-defined functions let modelers package DAX logic once and reuse it like a built-in function in measures, calculated columns and other functions.

Title graphic: DAX user-defined functions (UDFs) (Concept)

Type	Concept
Documentation	learn.microsoft.com/en-us/dax/best-practices/dax-user-defined-functions

Key points about DAX user-defined functions (UDFs)

VAL versus EXPR is not harmless syntax sugar in DAX user-defined functions. · DAX UDF VAL vs EXPR

Episodes about DAX user-defined functions (UDFs)

DAX UDF VAL vs EXPR

2025-11-18 · Video on YouTube

You thought VAL vs EXPR was harmless syntax sugar. In reality, it decides when your metrics are evaluated, which means the same function, same arguments can return a completely different “truth” — clean visuals, perfect totals, and numbers that are…

Articles about DAX user-defined functions (UDFs) (1)

Demystifying DAX UDFs: VAL vs. EXPR Explained
2026-08-28 · Mirko Peters
Welcome back to the podcast companion blog! In our latest episode, we took a deep dive into the powerful world of DAX User-Defined Functions (UDFs). If you have bee…

Glossary

Community wiki

Short info above, community knowledge below: add practical tips, examples or corrections. New contributions are reviewed first; trusted members publish directly.

Experts and companies for this topic

Nobody has listed this topic yet. Add it to your profile.

Sources

Documentation: learn.microsoft.com/en-us/dax/best-practices/dax-user-defined-functions
Feed for this topic (RSS): entity/dax-user-defined-functions/feed.xml
M365.FM episodes on this topic: 1
Articles on this topic: 1

Maintained by Mirko Peters (Microsoft MVP) · Last updated: 2026-11-03