DAX measure

A measure in Power BI is a named calculation written in DAX, the model's formula language. Unlike a column, it holds no stored values: it is evaluated each time a visual needs it, in the filter context of that visual. Total Revenue = SUM(Sales[revenue]) shows the whole total on a card, the total per region in a bar chart, and the total of the selected month when a slicer is set, all from the same definition.

Measures are where a report's logic lives: ratios, year-on-year comparisons, running totals. Writing them against the wrong model gives numbers that look plausible and are wrong, which is why they come after the model.

Where it appears in DASH:Gen

A generated Power BI project carries its measures in the model, each with a one-line description and a display folder, so the field list in Desktop is grouped. In the step-by-step route the measures stage shows the DAX verbatim before the report pages are built, and running the model stage again discards the measures so they are never left written against a model that has since changed. See the Excel to Power BI guide.

See also: Power BI from an Excel file · Star schema