Hi Peter!
You haven't answered my question about week numbering system. When
does week 2 start?
If Week 2 starts 8-Apr, then the formula could be:
=IF(MONTH(A1)<4,INT((A1-DATE(YEAR(A1)-1,3,31))/7)+1,INT((A1-DATE(YEAR(
A1),3,31))/7)+1)
You'll see that dates before April require the base date of the
preceding year's April. Otherwise, this year's April is the base date
for week.
But this system will always give you a week 53 because 365/7 gives 52
Modulus 1 and 366/7 gives 52 Modulus 2. You'll not avoid that problem
with any of the week numbering algorithms that you come up with.
Indeed with some Leap Years, 31-Dec can fall into week 54! (e.g.
=WEEKNUM("31-Dec-2028",1)
and
=WEEKNUM("31-Dec-2012",2)
--
Regards
Norman Harker MVP (Excel)
Sydney, Australia
(e-mail address removed)
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