DAX
Measures, calculated columns, filter context, and the functions behind Power BI's calculation language.
DAX
DAX (Data Analysis Expressions) is the formula language behind every measure and calculated column in Power BI — this section covers it from first principles through the specific functions you'll reach for most.
Start Here
Introduction
What DAX is, and where it fits into a Power BI model.
Basics
Core DAX syntax before diving into measures and functions.
Measures
The most important type of calculation in Power BI, and how they differ from calculated columns.
CALCULATE
The single most important function in DAX — modifying filter context.
Time Intelligence
Year-to-date, prior-period, and trend calculations.
DAX Function Reference
A categorized index of common DAX functions, linking to full explanations.
Where to Go Next
- DAX Patterns — ready-made patterns for totals, ranking, and percent of total.
- Data Modeling — the relationships and schema DAX measures depend on.
- DAX User-Defined Functions (UDFs) — new as of the June 2026 release, for packaging a calculation into a reusable, named function.
Want a starting point instead of writing one from scratch? Try the DAX Formula Builder — describe the calculation in plain English and get back a measure to check against what you learn here.