Identifying Duplicates after First Instance of Record

[aaron1976]

I am trying to identify duplicates without the remove duplicate tool but i want the first time it appears in the list to be identified as unique and all instances after to be identified as duplicate.

It is a list of account numbers down one column, say column B. Here is what I tried so far.

=IF(Countif(B:B,B2)>1,"Duplicate","Unique"). That identified duplicates and unique entries in the same manner as the conditional formatting highlight duplicate tool which is not what I want.

Does anyone have any ideas as to how to go abotu this task?

Expected result:

123456 Unique
123456 Duplicate
234567 Unique
234567 Duplicate

Any help would be greatly appreciated.

[Jonmo1]

Try

=IF(Countif(B$2:B2,B2)>1,"Duplicate","Unique")

[aaron1976]

That fixes my row at row 2 and will make everything as a duplicate. II did try the formula. I have 800 records and it turned evrything a duplicate.

[aaron1976]

I take that back, I think it works. Thank you so much.

[Jonmo1]

You're welcome.