Seem to have got it to work - for some bizarre reason I had to start a new
workbook, use the formula in there, it would then work in the original
document.

Unfortunately it turns out that the weeknum function doesn't return iso
standard week numbers anyway so not much use.

Fortunately the following site had the answer:

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

Thanks anyway.

Mike



"Unison Mike" wrote:

I am trying to use the weeknum function in excel 2003. However I am getting a
#NAME error, I have followed the helpfile instructions to make sute the
analysis toolpak is checked in the add-in menu, but this doesn`t seem to make
any difference. I can select the weeknum function from the formula wizard but
it still doesn't work.