A quick solution: Sort the entire data by the field you want to find. add a
helper column put a formula to check if the adjacent cells are the same like
=A1=A2. If you copy this down the column, all duplicates will show a True.
Put an auto filter. Filter for true and delete those rows. What you will be
left with will be only unique records. There may be a better/easier solution
available which I am not aware
of.
"skippy_prine" wrote:

I am trying to spot possible duplicate numbers in a ver large file. Is there
a formaula I could use to make sure none of these 13 digit account numbers
are listed twice within the same file?