Week Number First Day Of Week

[salahmost]

I use the following formula from:
http://www.cpearson.com/excel/WeekNumbers.aspx
to get the week number depending on first occurrence of "Saturday". For example, that Week 1 begins on the first Saturday of the year. The formula is:
=TRUNC(((A1-DATE(YEAR(A1),1,1)+MOD(7-WEEKDAY(DATE(YEAR(A1),1,1)),7))+6)/7)
Where A1 Contains the date I want to get its week number.
If A1 contains 1/1/2011 the result is 0 instead of 1 ....what'wrong ?

 

[Datsmart]

You will get the correct answer if you use the "Absolute Week Number" formula posted earlier on CPearson's page.

In your usage, would Saturday, January first be "week 1" of the year 2011 or the last day of week 52 of the previous year?

 

[barry houdini]

If week 1 starts on the first Saturday which week should apply to any dates before the first Saturday, are they in the last week of the previous year?

 

[salahmost]

Thank you ...
The "Absolute Week Number" formula does the trick.
--
If week 1 starts on the first Saturday which week should apply to any dates before the first Saturday, are they in the last week of the previous year?
It doesn't matter if 52 or 1 the first Saturday should be 1.

 

[barry houdini]

Are you only concerned with Saturdays or might you want to get the week number for another day of the week? If it's the former then absolute week numbers will work fine for you for any year but if it's the latter then you might not get the results you want for 2012 or other years......

 

[salahmost]

I'm only concerned with Saturdays. Although the The "Absolute Week Number" formula does the trick, I wonder if the formula related to special day on CPearson's page need to be modified.