SharePoint

If you need to determine which week of the month a particular date is in, use the following formula:

=(DATEDIF(DATE(YEAR(Datum);MONTH(Datum);1)-(WEEKDAY(DATE(YEAR(Datum);MONTH(Datum);1);2))+1;Datum+(7-WEEKDAY(Datum;2));"D")+1)/7

The formula above is for regions that use decimal comma format and week starts on Monday. If you use decimal dot and your weeks start on Sunday, use the following formula:

=(DATEDIF(DATE(YEAR(Datum),MONTH(Datum),1)-(WEEKDAY(DATE(YEAR(Datum),MONTH(Datum),1),1))+1,Datum+(7-WEEKDAY(Datum,2)),"D")+1)/7

The formula displays the week number in month, not in year.