WebToolArcSet and run a timer
Choose a common preset or enter hours, minutes and seconds. Start begins the countdown, Pause keeps the remaining time, and Reset returns to the duration currently entered in the fields.
Alarm and fullscreen
Sound playback requires a browser interaction, so preview the alarm once if you want to confirm your device volume. The default alarm plays once; repeating alarms are optional. Fullscreen keeps the countdown easy to read from across a room.
Background timing
While running, the timer tracks a target end time instead of subtracting a fixed amount on every screen update. This reduces drift when the browser slows background tabs, although a sleeping device can still delay when you hear the alarm.
Reliable browser timing
The countdown tracks a target end time instead of assuming every screen update arrives exactly on schedule. That helps the display recover from normal background-tab throttling. A sleeping device can still delay the audible alert until the browser resumes.
Fast ways to use it
Use a preset for common short timers, custom hours/minutes/seconds for exact durations, and fullscreen when the display needs to be readable from farther away.