vba

Function myhex2dec(h As String) As String
   Dim wf As Variant
   Set wf = WorksheetFunction
   myhex2dec = Format(CDec(wf.Hex2Dec(Left(h, 7))) * 2 ^ 28 + wf.Hex2Dec(Right(h, 7)), "0")
End Function

Source : https://www.mrexcel.com/board/threads/converting-a-hexadecimal-with-a-length-of-14-to-hexadecimal.1113336/