Calculate Time differance in label

I have created userform in which I have set 2 labels , Start time and End time , when I close the user form , i want to display a msg of time differance

Start label = Now() when form loaded or showed
End label = now()-start label

but msg showing empty


pl. suggest

Start = Timer
msgbox "Duration: " & Timer - Start

Thanx
Is it possible to display countdown timer in label of 00:30:00 (30 min) which can be further set as required time .It will be better if display hh:mm:ss:ms (milliseconds)

Thanx
Is it possible to display countdown timer in label of 00:30:00 (30 min) which can be further set as required time .It will be better if display hh:mm:ss:ms (milliseconds)

For starters, using TIME vs. Timer:

    Dim TimeIs  As Date, _
        StopTime    As Date, _
        TimeZero    As Date

    TimeZero = Time

'some other stuff between the start and stop times...

    StopTime = Time
    TimeIs = StopTime - TimeZero
    UserForm1.Label1.Caption = TimeIs
    UserForm1.Show