Pls help with Excel Function

[TotallyConfused]

I have a list of thousands of records. I need to identify duplicates. There
can be more than one duplicate. I am using this function
=IF(countif(B$2:B$3000,B2)>1, "Duplicate","No Dup"). This marks all the same
rows duplicate. I would like for the function to look at the first dup not
mark it dup and only mark the next row if dup as Duplicate. For instance:

Duplicate testing No dup testing
Duplicate testing Duplicate testing
Duplicate testing Duplicate testing
Duplicate Monday No dup Monday
Duploicate Monday Duplicate Monday

 

[Lars-Åke Aspelin]

I have a list of thousands of records. I need to identify duplicates. There
can be more than one duplicate. I am using this function
=IF(countif(B$2:B$3000,B2)>1, "Duplicate","No Dup"). This marks all the same
rows duplicate. I would like for the function to look at the first dup not
mark it dup and only mark the next row if dup as Duplicate. For instance:

Duplicate testing No dup testing
Duplicate testing Duplicate testing
Duplicate testing Duplicate testing
Duplicate Monday No dup Monday
Duploicate Monday Duplicate Monday

Try this formula in cell C2

=IF(COUNTIF(B$2:B2,B2)>1,"Duplicate","No Dup)

Copy it down column C.

The only difference to the formula that you have is that B$3000 is
replaced with B2, i.e. only the rows above and including the current
row are included in the counting.

Hope this helps / Lars-Åke