Private Sub Command1_Click()
 
Dim Sek_gesamt As Long
 
Dim sTime1 As String, sTime2 As String, sDate1 As String, sDate2 As String
 
sTime1 = Text1.Text
sTime2 = Text2.Text
 
sDate1 = CDate(Format$(Now, "m-d-yy"))
 
' Wenn sTime2 < sTime1
sDate2 = DateAdd("d", IIf(sTime2 < sTime1, 1, 0), sDate1)
 
' Zeit-Differenz in Sekunden
Sek_gesamt = DateDiff("s", CDate(sDate1 & " " & sTime1), _
  CDate(sDate2 & " " & sTime2))
 
' Und jetzt ins Format hh:nn:ss umwandeln
MsgBox "Zeit-Differenz: " & _
  Format$(((Sek_gesamt / 60) / 60), "00") & ":" & _
  Format$(((Sek_gesamt / 60) Mod 60), "00") & _
  ":" & Format$((Sek_gesamt Mod 60), "00")
 
End Sub