BrowserTools

Online Alarm Clock

Set an alarm while the tab is open

By Guga — BrowserTools maintainer, Tbilisi, Georgia Updated 2026-09-17
Free Private No uploads
What is Online Alarm Clock?

A single-alarm tool for a tab you are already sitting in. Pick a time, type a label like 'medication' or 'call the vet', and press Set alarm; the panel then counts down in hours, minutes and seconds until it fires. When it rings, the browser tab title is prefixed with a bell so you notice it even if the window is behind something else, the label is shown prominently, and the chime repeats every 900 milliseconds until you stop it. The clock display updates once a second and shows the full date underneath. This is a wall-clock alarm rather than a countdown: it matches on the hour and minute, so it does not accumulate drift, and a time already past today is treated as tomorrow. One alarm at a time — it is for a nap, a break or a reminder within the hour.

Set an alarm to ring at a specific time — for naps, breaks or reminders — with a gentle built-in chime. Keep the tab open and it will wake you right on time.

Private Online Alarm Clock In Your Browser

Online Alarm Clock is processed locally with client-side JavaScript. Your files never touch a server, and there is no queue to wait in.

Step-by-Step

How to use Online Alarm Clock

1

Choose an alarm time in the time picker and, optionally, type a label to identify it.

2

Press Set alarm; the panel switches to a countdown showing hours, minutes and seconds until it fires.

3

When it rings, the tab title changes and the chime repeats until you press Stop alarm.

4

Press Cancel alarm to disarm it without waiting for it to go off.

Key Capabilities
  • The alarm matches on hour and minute against the system clock, so a background-tab interval delay cannot accumulate into a wrong firing time.
  • A countdown in hours, minutes and seconds is displayed from the moment the alarm is armed.
  • The tab title is rewritten with a bell prefix while the alarm rings, so it is visible even when the window is not focused.
  • The chime repeats on a fixed 900 ms cycle until stopped, and the alarm label is shown on the ringing panel.
Common Use Cases
  • Someone on a long call sets a 45-minute alarm so the meeting cannot overrun.
  • A person working from home sets a labelled lunch alarm so they actually stop at midday.
  • A student sets an alarm for a timed revision block while the tab stays open on a second monitor.
Clear Answers

Frequently Asked Questions

Will it wake me if I close the tab?
No. This is a web page, not an operating system alarm. Keep the tab open — and browsers throttle timers in hidden tabs, so a fully backgrounded tab may notice the alarm a little late.
Can I set several alarms for the morning?
One at a time. The tool holds a single alarm; set the next after the current one has been stopped or cancelled.
What if the time I pick has already passed today?
It is treated as tomorrow. The countdown adjusts accordingly, so an alarm set for 07:00 at 09:00 will show roughly twenty-two hours remaining.
Does the alarm survive a page refresh?
No. Arming state lives in the page, and reloading clears it.