If you've just started with Power BI, you've probably written a few basic measures ,things like SUM([Sales]) or AVERAGE([Revenue]). They work fine. Until you want something a little more specific. What if you only want total sales for a particular region? Or sales for just this year? Or sales for a specific product, even when your chart is filtering for something else? That's where CALCULATE comes in. It's the most important function in DAX and once you understand it, a wh