Excel ISO Week Numbers - Adding Weeks

[bennygod]

Hi all

I'm using the following formula to return the current ISO week number (this week we are in week 45, for example):

=1+INT((C2-DATE(YEAR(C2+4-WEEKDAY(C2,2)),1,5)+WEEKDAY(DATE(YEAR(C2+4-WEEKDAY(C2,2)),1,4),2))/7)

Cell C2 is just the current date: =TODAY()

So the ISO week formula returns 45 for today and thru' until Sunday. If I want to plan to have something done within 5 weeks I want to put the time to do it as 5 and then convert this back to give me the correct deadline ISO week number. No it is nota simple 45+5 as in this case that would work. If my lead time was in fact 20 weeks, it would not be 45+20 as this would return 65, which is not a week number. In this case the answer should be week 12 (since this year is a 53 week year according to ISO).

Anybody any ideas?

Much appreciated, thanks!!!

 

[WinteE]

Just add 35 ( 5 * 7 ) to the date.