Sub Main()
Debug.Print GetColumnRef(3)
End Sub
Function GetColumnRef(columnIndex As Integer) As String
Dim numAlpha As Integer
Dim firstLetter As String
Dim secondLetter As String
Dim remainder As Integer
numAlpha = columnIndex \ 26
Select Case columnIndex / 26
Case Is <= 1 'Column ref is between A and Z
firstLetter = Chr(columnIndex + 64)
GetColumnRef = firstLetter
Case Else 'Column ref has two letters
remainder = columnIndex - 26 * (columnIndex \ 26)
If remainder = 0 Then
firstLetter = Chr(64 + (columnIndex \ 26) - 1)
secondLetter = "Z"
GetColumnRef = firstLetter & secondLetter
Else
firstLetter = Chr(64 + (columnIndex \ 26))
secondLetter = Chr(64 + remainder)
GetColumnRef = firstLetter & secondLetter
End If
End Select
End Function