Excel function WEEKNUM and change week start day.

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

WEEKNUM(serial_number,[return_type])

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_TypeStart Day of Week
1Sunday
2Monday
11Monday
12Tuesday
13Wednesday
14Thursday
15Friday
16Saturday

I used

How to use Date Function in Excel 2010

How to use Date Function in Excel 2010

=WEEKNUM(A1,14) and got my result.