Built for the back row
The ring is the point. Digits alone make a student calculate how much time is left; a shrinking arc shows it without reading, which is what you want when the room is working and you do not want to interrupt. The ring turns amber in the last fifth of the time and red when it runs out, so the state of the room is legible from the doorway.
No advertising on this page
This page carries no ads and never will, because it is designed to be projected in front of a class. Every other page on this site is ad-supported; this one is the deliberate exception. You can put it on a screen in a room full of children without worrying about what appears next to it.
Using it
Tap a preset or type any number of minutes. Full screen strips everything but the ring, and Escape brings the page back. The screen is kept awake while the timer runs, so it will not dim partway through independent work. When time runs out it chimes, announces it, and flashes the display, which carries across a noisy room better than sound alone.
Where a visible timer helps
Timed independent work, exam practice, turn-taking in group tasks, and transitions between activities. The research on this is unglamorous but consistent: making remaining time visible reduces the number of times a class asks how long is left, and shortens the transition itself. It also gives students who struggle with time estimation something concrete to pace against.