User Guide
- Open the tool above — it is ready to use immediately.
- Enter any required details.
- Get your result instantly.
About the Online Alarm Clock
An alarm you can set in a browser tab, with no app to install and no permissions to grant. Useful when you are working at a computer and need a nudge — a meeting in twenty minutes, something in the oven, a break to actually take, a call in another timezone — and reaching for your phone means picking up your phone.
What it does
Set a specific time, or use a quick option for 5, 10, 15, 30 or 60 minutes from now. Each alarm takes a label so several at once stay distinguishable, and the list shows a live countdown to each. When one fires it plays a repeating tone, flashes the browser tab title, and offers Snooze 5 minutes or Stop. If you have allowed notifications, a desktop notification appears too.
The honest limitation
This runs in your browser, so the tab has to stay open. Close the tab, quit the browser or shut the laptop lid and the alarm cannot ring — there is no server involved and nothing scheduled outside the page. For anything you genuinely must not miss, use your phone. This is for the things you would otherwise set a mental reminder for.
Two smaller points. Sound requires one interaction with the page first, because browsers block audio until a user clicks something — pressing “Set alarm” satisfies that, which is why the test-sound button exists to confirm it works. And browsers throttle timers in background tabs, so the countdown display may update lazily when the tab is hidden; the alarm itself compares against your device clock rather than counting ticks, so it still fires at the right moment.
The tone
The alarm sound is generated in the browser with the Web Audio API — a two-tone beep, not an audio file. That means nothing extra to download and no delay before it plays, and it works offline once the page has loaded.
Related timing tools
For counting down a fixed duration with a visible clock, use the Countdown Timer. For timing something that has already started, the Online Stopwatch with lap times. For structured work intervals, the Pomodoro Timer. And to work out what time an alarm should be set for across timezones, the Time Zone Converter.
Frequently Asked Questions
How do I set an online alarm?
Pick a time and press “Set alarm”, or use a quick option for 5 to 60 minutes from now. Add a label if you are setting several. The alarm rings in this browser tab, so leave the page open.
Will the alarm work if I close the tab?
No. It runs entirely in your browser, so closing the tab, quitting the browser or shutting the laptop stops it. For anything critical, set your phone as well.
Why is there no sound?
Browsers block audio until you interact with the page. Pressing “Set alarm” unlocks it — use the “Test sound” button to confirm before relying on it. Also check that the tab is not muted and your system volume is up.
Does the alarm still fire if the tab is in the background?
Yes. Browsers slow background timers, so the countdown display may update lazily, but the alarm compares against your device clock rather than counting ticks, so it fires at the correct moment.
Can I set more than one alarm?
Yes, as many as you like. Each carries its own label and countdown, and the list stays sorted by which fires next.
Does snooze work?
Yes — snooze pushes that alarm five minutes forward and stops the sound. Stop removes it entirely.