Eighteen minutes is a TED-length talk, which makes it a useful rehearsal timer even if your real talk is shorter. It also covers a sheet-pan dinner check or a commute playlist of four songs.
If you are rehearsing, stand up. Sitting through a practice talk hides the places you rush. 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 18 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 18 minutes timer on a projector?
Press start, then F or the fullscreen button. Classroom mode hides the writing so the digits fill the wall. If you are rehearsing, stand up. Sitting through a practice talk hides the places you rush.
What is 18 minutes actually good for?
Eighteen minutes is a TED-length talk, which makes it a useful rehearsal timer even if your real talk is shorter.
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.