I want to calculate typing speed

Hi,

Can anyone help me...
In my aplication I want to calculate typing speed...so in that I take 2 textboxes 2 buttons-stop, speed on gotfocus I start my timer & on stop I stop my timer, just I want to find out difference between start time & end time.

Thanks in advance...

when u start the timer note system time and also do the same when u stop it and finally find out the difference.