Sub BenC()
Dim der As Long
Application.ScreenUpdating = False
With ActiveSheet
If .FilterMode Then .ShowAllData
der = .Cells(Rows.Count, "b").End(xlUp).Row
If der < 3 Then Exit Sub
.Range("c3:c" & der) = .Range("b3:b" & der).Value
.Range("b3:b" & der).ClearContents
End With
End Sub