Forty-seven minutes is an untidy prime, which is useful when a round number invites people to fill time. One paper, one problem, one design critique.
Stand at the end. A forty-seven minute sit needs a physical stop or you will keep sitting. Press space to start or pause, R to reset, and F for fullscreen. The screen can stay awake after you start, using the wake lock your browser allows. Pick the alarm before you begin. A bell, a chime, a beep, or a short digital pulse all come from the Web Audio API, so there is no sound file to wait on.
This page is the 47 minutes countdown and nothing else is running underneath it. Related lengths are linked under the guide if you want a neighbor, and the timer itself stays above the fold.
Questions
How do I run a 47 minutes timer on a projector?
Press start, then F or the fullscreen button. Classroom mode hides the writing so the digits fill the wall. Stand at the end. A forty-seven minute sit needs a physical stop or you will keep sitting.
What is 47 minutes actually good for?
Forty-seven minutes is an untidy prime, which is useful when a round number invites people to fill time.
Will the countdown drift if I switch tabs?
No. The end is a timestamp. The display is the gap between that timestamp and now, so a background tab does not lose seconds the way a ticking counter would.