What do you have in A165.


"niwrad" wrote in message
...
I'm using Excel 2003 and in a particular worksheet, the Auto Extend
Formulas
doesn't work on a particular formula. I've turned on the Auto Extend
option
and it does work on another formula in the same worksheet. The problematic
formula is:

=WEEKNUM(DATEVALUE(TEXT(A165,"dd/mm")),2)-37+52

Can someone kindly help explain why there's a problem here?