Private Sub Command1_Click()
 
  If Text1 = "" Or Text2 = "" Or Text3 = "" Then
    MsgBox "Bitte fülle alle Felder aus!", vbOKOnly, "Error"
    End If
 
   Dim Minuten As Double
   Dim stunden As Double
   Dim mpromin As Double
   Dim kmproh  As Double
 
   Minuten = DateDiff("s", Text1, Text2) / 60
   Minuten = Round(Minuten, 3)
   stunden = Round(Minuten / 60, 3)
 
   mpromin = Round(Text3 / Minuten, 3)
   Text4 = mpromin
 
   kmproh = Round(Text3 / 1000 / stunden, 3)
   Text5 = kmproh
   Label4.Visible = True
   Label5.Visible = True
 
End Sub