I use the following formula, which works very well
=IF(AND(A1="",C1=""),"",IF(B2="","",A1+1))

"Biff" wrote:

Hi!

You can do this with formulas depending on what type of
numbering system you want to use. Something like this
maybe:

In cells A10:An:

=IF(B10="","",ROW()-9)

This will start with a number sequence of 1.

Biff

-----Original Message-----
How can Excel number all cells in A1 to automatically
include a sequencial numbering system as soon as an entry
in the adjacent cell is updated?

Eg, Cells 10-100 are blank. When a user enters data into
B10, B11 - B100 etc. I want Excel to automatically enter
in Column A a sequential number used as an identifier.

Thanks.
F
.