Classroom timer
The classroom timer is set for a lesson rather than a desk: 20-minute silent work blocks, a 5-minute break between them, a 15-minute break after 4 blocks, and a single chime when time is up. The display reads from the back row when projected, and the tomato fills as the block runs, so students can glance up and see the time left without asking. There is no background sound by default, because a classroom already has enough.
It suits teachers running independent reading, silent writing, timed practice, or group work that needs a visible end point, and it works for exam-style tasks where students should know how long they have without you announcing it. Twenty minutes is a comfortable stretch for most middle and high school classes, and shorter blocks fit younger students.
It is not designed for whole-class instruction or discussion, where a countdown on the wall pulls attention toward the clock and away from the conversation. Turn it off for those parts of the lesson and bring it back for the work. Nothing is stored or tracked, so it runs on a school laptop or shared projector with no account and no setup beyond opening the page.
Questions
how long should a focus block be for students in class
Twenty minutes works for most secondary classes, which is why this timer starts there. Primary classes often do better with 10 or 15. Watch when the fidgeting starts and set the block a little shorter than that.
does the classroom timer need internet or an account
It needs a connection to load the page the first time. After that it runs in the browser with no login, and the chime works even when the tab has been open all lesson. Nothing about your class is recorded.
can students see the timer from the back of the room
Yes. The numbers and the filling tomato are sized to be read from across a room when projected or shown on a classroom display, and they scale with the size of the window.