Column Numbers to Letters

This is extremely useful if you need to switch between the Range object and the Cells object.
Remember that using column letters in your code makes it significant easier to understand and quicker to debug.

Public Function Col_Letter(ByVal iColNo As Integer) As String 
Dim sstartletter As String 
   On Error GoTo AnError 
   Col_Letter = Left(Cells(1, iColNo).Address(False, False), _ 
                  Len(Cells(1, iColNo).Address(False, False)) - 1) 
   Exit Function 
AnError: 
   Call MsgBox(Err.Number & " - " & Err.Description) 
End Function 

Public Function Col_Letter2(ByVal iColNo As Integer) As String 
Dim sstartletter As String 
   On Error GoTo AnError 
   Select Case iColNo 
      Case 0:         Col_Letter2 = Chr(90) 
      Case Is <= 26:  Col_Letter2 = Chr(iColNo + 64) 
      Case Else 
         If iColNo Mod 26 = 0 Then 
            Col_Letter2 = Chr(64 + (iColNo / 26) - 1) & Col_Letter(iColNo Mod 26) 
            Exit Function 
         End If 
         sstartletter = Chr(Int(iColNo / 26) + 64) 
         Col_Letter2 = sstartletter & Col_Letter2(iColNo Mod 26) 
   End Select 
   Exit Function 
AnError: 
   Call MsgBox(Err.Number & " - " & Err.Description) 
End Function 

Converting a Column Letter to its equivalent Column Number

Public Function Col_Number(ByVal sColChar As String, _ 
                  Optional ByVal sWshName As String = "") _ 
                           As Integer 
Dim istartnumber As Integer 
   On Error GoTo AnError 
   If Len(sColChar) = 1 Then 
      If sWshName <> "" Then _ 
         Col_Number = Worksheets(sWshName).Range(sColChar & "1").Column 
      If sWshName = "" Then Col_Number = Range(sColChar & "1").Column 
   Else 
      istartnumber = Range((Left(sColChar, 1)) & "1").Column 
      Col_Number = ((istartnumber)) * 26 * (Len(sColChar) - 1) + _ 
                                      Col_Number(Right(sColChar, Len(sColChar) - 1)) 
   End If 
   Exit Function 
AnError: 
   Call MsgBox(Err.Number & " - " & Err.Description) 
End Function