Formula for week number

[fernipascual]

Hi there:

I want to say that this forum has been SO helpful to me and I appreciate the quick responses!

I have a list of dates going back to 2005 and I want to assign week numbers to them. For example,
1/7/2005 would be week 1. (=weeknum,a1).
12/31/2005 would be week 53
1/5/2006 would be week 54 (not week 1)
12/31/2006 would be week 106 (or 105, not sure)


My question is how to assign week numbers after the 53rd week of a year if I have a long list that begins in 2005 all the way to 2011 and beyond.

Thanks much

 

[Wesnet]

In A1, put 1/7/2005
In A2, put 1/1/2011
In B2, put =(A2-A1)/7 (it will show as 313, the 313th week).

You can play around with the start date in A1 to get this perfect.