Function columnNumber(colLetter As String) As Integer

    Dim colNumber As Integer
    Dim i As Integer

    colLetter = UCase(colLetter)
    colNumber = 0
    For i = 1 To Len(colLetter)
        colNumber = colNumber + (Asc(Mid(colLetter, Len(colLetter) - i + 1, 1)) - 64) * 26 ^ (i - 1)
    Next

    columnNumber = colNumber

End Function