I have been using week number function from quite some time now, but I came across a situation where I need to change week start from Sunday to Thursday.
Syntax for WEEKNUM
Till now I had never used return type argument as it was optional but this does the trick. By default if not provided its 1 i.e. Sunday. But it has other options as well
|Return_Type||Start Day of Week|
How to use Date Function in Excel 2010
=WEEKNUM(A1,14) and got my result.