Free, no account, no ads. Your class list is stored in this browser and never sent anywhere.
Browsers throttle background tabs, so a timer that counts its own ticks loses minutes the moment you switch to your slides — which is exactly what every teacher does thirty seconds after starting one.
This reads the clock instead of counting. Switch away for ten minutes and come back and it is correct, because it never tried to keep count in the first place.
It also holds the screen awake while running, so the projector does not sleep in the middle of a silent ten minutes.
Three states, not two. Silent matters more than it sounds: during a test, or with a child who finds a sudden noise genuinely distressing, an alarm is not a small problem. The bar emptying is enough.
Whichever you choose, the sound is prepared on the same click that starts the timer. Browsers refuse to play audio that was not started by a deliberate action, and a timer whose alarm fails silently at the end fails at the only moment that mattered.
The most-used control in a real lesson is not start or stop, it is "you have one more minute". Plus and minus adjust while it is running without resetting anything.
Yes. It reads the system clock rather than counting ticks, so background throttling does not affect it.
Yes — loud, soft and silent. Silent is a full state, not a muted one.
Yes, plus and minus a minute work mid-run and keep the timer going.