I knew you could go to Google.com and type in such things a "convert x to y" (i.e. miles to kilometers, dollars to pounds, ounces to cups), but I did not know Google search also worked as a timer!
Try it. Just go to Google.com and type in "set timer for x minutes." It starts counting down. It has sound that beeps when done, but you can mute it. Of course, if the timer goes off, you'd better be around to hit "ok" or be annoyed!
I am going to guess it would work on my iPad and would make a great timer for cooking!