Hi Mike,

But it does not limit the number
of charaters to one !!! :((

O yes, silly me. Like this:

If the cell is cell A1, use this custom formula for the validation:

=AND(NOT(ISNUMBER(VALUE(A1))),LEN(A1)<=1)

Regards,

Jan Karel Pieterse
Excel MVP
http://www.jkp-ads.com