Message if duplicate found

Hello all,

I'm requesting again for any help: This is what I'm currently working:

My user is allowed to type certain numbers in Column A (range: A19 to 82). I need help for a macro that will alert the user that that value has been entered, then disallow entry of that duplicate value.

Any help is much appreciated, as always.

Thanks

WK

Hello WhiteKelso,

Since you are allowing only certain numbers, why not use Data Validation on the cell range? This would be easier and faster than writing a macro.

Sincerely,
Leith Ross

to a sheet module

Private Sub Worksheet_Change(ByVal Target As Range)
With Target
    If (Not Intersect(.Cells, Range("A19:A82")) Is Nothing) * _
       (Not IsEmpty(.Value)) Then
       If WorksheetFunction.CountIf(Range("A19:A82"),.Value) > 1 Then
           MsgBox "Duplicate"
           Application.EnableEvents = False
           .ClearContents
           Application.EnableEvents = True
       End If
    End If
End With
End Sub