remove duplicats

Hi,

I don't believe that this task can be done using a formula!

You definitely need to VBA code associated with an event to do so.

So, I would suggest this one:

Private Sub Worksheet_Change(ByVal Target As Range)
    
    On Error Resume Next
    Application.EnableEvents = False
    
    If Not Intersect(Target, Range("A:A")) Is Nothing Then
        Range("A:A").RemoveDuplicates Columns:=1, Header:=xlYes
    End If
    
    On Error GoTo 0
    Application.EnableEvents = True
    
End Sub

Please find it in the attached file.

Try to enter a duplicate barcode and see how it will be gone immediately.

And, please note that this code is only applied to column A, but you can modify it as you want.

Hope that helps