Private Sub Form_Load()
    Dim Startdatum As Date
    Dim Enddatum As Date
 
    Startdatum = "10.04.2013 12:45"
    Enddatum = "12.04.2013 16:30"
 
    Zeitdifferenz = DateDiff("n", Startdatum, Enddatum)
    MsgBox Zeitdifferenz & " Minuten"
End Sub