Sounds like ISO week number. Take a look at
http://www.cpearson.com/excel/weeknum.htm

--
HTH

Bob Phillips

"MickeW" wrote in message
...
I work in a Swedish environment, and would like to use the function
Weeknum,
the thing is, that Sweden uses a different way to number our weeks, for
example, the date 2005-01-01, is weeknumber 53, but if I use the function
Weeknum, it computes to weeknum 1. Is there anyone who has any suggestions
of
how to tackle that problem?

MickeW