What exactly is the problem? You're starting the Stopwatch when the key goes down and stopping it when the key goes up. That will measure time the key is depressed, and you're then displaying that time in the Output window. So, that's what you've got. What does it not do that you want it to do? What does it do that you don't want it to? It's your app so these are things that you must know, so you need to explain it to us.