DAX Calendar Week

In DAX, if you need to calculate the calendar week (KW), you can use WEEKNUM function.

If you want to use the ISO convention for counting the weeks, you need to use [Return Type] = 21.

KW = FORMAT( DimCalendar[Date]-WEEKDAY(DimCalendar[Date],2) + 1, "yy") & "KW" & FORMAT(WEEKNUM(DimCalendar[Date],21), "00")