Online school bell: class bells on a schedule

An online tool that replaces a school bell with a relay timer: class start and end bells on a schedule, a warning bell, melodies instead of bells and a full-screen countdown to the end of class. A bell schedule takes a minute to build and prints on a single sheet.

How to use

Set the schedule

Pick a ready-made grid, build one with the generator or paste it as text from the school website. Set up Saturday and the shortened day on their own tabs.

Choose a bell or melodies

Pick the start and end of class sounds, the warning bell and the volume. For melodies instead of bells, upload files — the clip and volume adjust themselves.

Turn on the bell

Press “Turn on bell” and leave the tab open all day. The display can go on a projector or into a mini window.

Set the schedule once — the bells and melodies take it from there

Off

Schedule

Class starts

Class ends

Warning bell before class, min

Bell length 3 s Volume 80%

Melodies instead of bells

Clips of songs or music play instead of the bell: you can adjust the start and length, and the volume levels itself. Melodies are stored in this browser.

Add melodies

Melodies change every month

Separate schedule on Saturday Vacations and holidays — the bell stays silent

From To

School or class name — for printing Ring by exact time, not by the computer clock PIN protection

Move to another computer

The file carries the schedule, days, vacations and sounds; melodies have to be added again on the new computer.

Bell check

The computer clock hasn't been checked yet.

Features

Rings on time, even in a minimized tab

Each bell is queued on the sound card a minute before its moment, so it sounds on the exact second even when the browser slows down a background tab. The day log shows which bell rang and which was missed, and why.

Melodies instead of bells

Upload clips of melodies and they play instead of the bell. The clip's start and length are adjustable, the volume levels itself, and melodies can be assigned by month: they switch on the 1st without you doing anything.

Regular, Saturday and shortened schedules

Three day types and ready-made grids: 45- and 40-minute classes, a second shift, 90-minute college classes, first grade. “Shortened today” turns on with one click and switches back to the regular schedule at midnight; during vacations the bell stays silent.

Warning bell and custom signals

A warning bell 1–5 minutes before class with its own sound, plus extra signals at set times — assembly, lunch, end of shift. Two bells in the same minute merge into one.

Full-screen and mini-window countdown

Large digits counting down to the end of class or break are readable from the back row and on a projector. In Chrome and Edge the countdown opens in a small window on top of a presentation, and the tab title always shows the time left.

Bell schedule on paper, by link and as a file

The finished schedule prints or saves as PDF with the school name, moves to another computer by link and QR code, and a PIN keeps students from turning off the bell.

Questions and answers

Will the bell ring if I minimize or close the tab?

A minimized tab rings: each bell is queued on the sound card ahead of time, and a browser that slows down background pages doesn't shift it — you can verify this with the “Test in background” button. A closed tab can't ring on any website. The computer also must not go to sleep, and on a phone the bell works only with the screen on and the page open.

How do I use melodies instead of bells?

In the “Melodies instead of bells” section, upload melody files: the first one is set for class start and end automatically. For each melody you can set which second it starts at and how many seconds it plays — ten by default. If melodies change every month, turn on “Melodies change every month” and assign them by month: they switch on the 1st by themselves. The files are stored in this browser, so on another computer you need to upload them again.

What happens if the computer fell asleep and woke up after a bell?

A missed bell won't ring after the fact — the late window is a minute and a half: a bell for third period in the middle of fourth throws off the whole school. But it doesn't vanish silently either: the day log shows “missed — tab was asleep from 10:31 to 11:02”, and a missed-bells counter appears above the schedule.

How do I set up a shortened day?

Press “Shortened today” — until midnight the bell rings on the shortened schedule, and tomorrow it goes back to the regular one by itself. The shortened schedule is set on its own tab: a ready-made 30-minute grid or your own times.

Can I open the bell in several tabs?

Yes, but only one will ring: other tabs in the same browser show the display and say that another tab is ringing — so there's never a double bell. Schedule edits in one tab appear in the others right away. If the bell is on at two different computers, both will ring.

How accurate is the bell time?

The bell goes off on its exact second by the computer clock. The tool checks that clock against the server and warns you if it drifts by more than five seconds; you can turn on “Ring by exact time”, and then the computer's drift no longer matters.

How do I print the bell schedule?

The “Print” button in the schedule header puts the regular, Saturday and shortened schedules with breaks and the school name on one sheet, and the “PDF” button next to it saves the same sheet as a file. The easiest way to move the schedule to another computer is the “Link” button: it gives an address and a QR code for a phone.

💡 Want us to improve this tool just for you?

We can! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.

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Published 12 Sep 2026 Updated 13 Sep 2026 Author: The Supreme