Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long) 'für 
' Sleep
Private Sub Command1_Click()
Dim i As Long, Zeit As Long, ProzentWert as Byte
   Zeit = CLng(Form1.DTPicker2.Value) - CLng(Form1.DTPicker1.Value)
   If Zeit > 0 Then
      Form2.ProgressBar1.Min = 0
      Form2.ProgressBar1.Max = 100
      For i = Zeit To 0 Step -1
         Sleep 50 'Für jeden Tag (i) irgendwas machen
         ProzentWert = CLng((100 * i) / Zeit)
         Form2.ProgressBar1.Value = ProzentWert 
         Form2.Label1.Caption= ProzentWert & "%"
         Form2.ProgressBar1.Refresh
         Form2.Label1.Refresh
      Next i
   End If
End Sub