Another simple question, with a simple answer! At some point, you will need to extract, determine, the extension of a file. Below is a straightforward function to do so.

'---------------------------------------------------------------------------------------
' Procedure : GetFileExt
' Author    : CARDA Consultants Inc.
' Website   : http://www.cardaconsultants.com
' Purpose   : Return the file extension from a path\filename input
'
' Input Variables:
' ~~~~~~~~~~~~~~~~
' strFileWPath - string of a path and filename (ie: "c:\temp\test.xls")
'
' Returns:
' ~~~~~~~~
' xls
'
' Revision History:
' Rev       Date(yyyy/mm/dd)        Description
' **************************************************************************************
' 1         2012-Feb-24                 Initial Release
'---------------------------------------------------------------------------------------
Function GetFileExt(ByVal strFileWPath As String)
On Error GoTo Error_Handler

    GetFileExt = Right(strFileWPath, Len(strFileWPath) - InStrRev(strFileWPath, "."))

Error_Handler_Exit:
    On Error Resume Next
    Exit Function

Error_Handler:
    MsgBox "The following error has occurred." & vbCrLf & vbCrLf & _
            "Error Number: " & Err.Number & vbCrLf & _
            "Error Source: GetFileExt" & vbCrLf & _
            "Error Description: " & Err.Description, _
            vbCritical, "An Error has Occurred!"
    Resume Error_Handler_Exit
End Function