Try this link over to Chip Pearson's site. I think this may be what you're
looking for...

http://www.cpearson.com/excel/weeknum.htm

HTH
"ciccio" wrote in message
...
Excel gives an incorrect calendard week number.
=num.week(A1) gives 4 if in A1 is 21/01/05. Actually 21/01/05 is in week
3!
Why? and more important , may I correct it?