Online Alarm Clock
Set an alarm for a specific hour and minute and let it sound while the tab stays open.
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Set a target hour and minute on the 24-hour clock, arm the alarm, and this tool watches your device's current time until it matches — then it plays a sound to get your attention. The live clock at the top shows the exact time it is comparing against. It runs in the browser with nothing to install, which is handy for a quick reminder at your desk.
It goes by your device clock, on the 24-hour format
The alarm fires when your computer or phone's own clock reaches the time you set, so it is only ever as accurate as that clock. Enter the time in 24-hour format — for example 13:30 for half past one in the afternoon and 08:00 for eight in the morning — which removes any AM/PM confusion. The current-time readout uses the same clock, so if it looks wrong, your device's time or time zone is the thing to check.
The tab has to stay open — and sound has to be allowed
Because the alarm runs in this page, it can only sound while the tab is open (a pinned or background tab is fine, but a closed one is not). Browsers also block audio from playing until you have interacted with the page, so arming the alarm with a click is what gives it permission to make noise later. If nothing sounds, check that the tab is still open, your volume is up, and the site is not muted.
Frequently Asked Questions
How do I enter the time?
In 24-hour format: hours 0–23 and minutes 0–59. So 2:45 PM is 14:45 and 9:05 AM is 09:05. This avoids any AM/PM mix-up.
Will it ring if I close the browser?
No. The alarm runs inside this page and can only sound while the tab is open. It will not fire if the tab or browser is closed.
I set it but heard nothing — why?
Usually the volume was down, the tab was muted or closed, or the browser had not been allowed to play audio. Arming the alarm with a click grants that permission; make sure the tab stays open with sound on.
Is the alarm as accurate as a real clock?
It fires when your device clock reaches the set time, so it is exactly as accurate as your device. If your system time or time zone is off, the alarm will be too.