Online timer

Tap a preset (1, 5, 10 or 25 minutes) or type hours, minutes and seconds, then press Start. You can pause, add a minute or reset at any time. When the timer reaches zero, the alarm plays and the page shows the exact UK time it finished.

Classroom display: press Classroom display (or F) to fill the screen with large, high-contrast digits that can be read from the back of a room. Press Escape or Exit classroom display to return.

Sharing: Copy link gives a link that opens this timer with the same time and label already set, which is handy for a lesson plan or a group chat.

Accuracy: the timer works from the clock, not by counting ticks, so it stays right if you switch tabs. Phones and browsers can pause background tabs, though, so the alarm may sound late if the tab is hidden; the time shown is correct as soon as you come back. While the timer runs we ask your device to keep the screen on, where it supports that. The alarm is a sound made in your browser; no audio is downloaded.