TimerPlanOnline alarm clock
Alarm
0:00
Leave this tab open — the sound is scheduled inside the page, so it rings even if the tab is in the background, but not if the tab is closed.
One thing a month worth timing
MonthlyOne thing a month worth measuring or capping with a clock — a payroll trap, a nap length, a meeting that never gets added up. Two sentences and the tool.
Try also
Can a browser alarm clock be trusted?
The TimerPlan alarm rings from a background tab because the tone is booked onto the audio clock the moment you set it — but it cannot ring if the tab is closed, the browser is quit or the machine is asleep, and no web page can. That limit is worth knowing before you rely on one to get up.
Within it, a browser alarm is genuinely useful: a laptop that stays awake on a desk, a spare tab on a work machine, a shared screen in a room. For those, this page is more reliable than most, because it does not wait until the moment arrives to try making a sound — by then a frozen tab has already missed it.
For waking up, the alarm built into a phone is the right tool. It is part of the operating system, which is allowed to wake the device; a web page is not.
Times can be typed the way you say them, and the awkward hour is worth spelling out:
| Typed | Understood as |
|---|---|
6:45 am | Quarter to seven in the morning |
18:30 | Half past six in the evening |
0645 | The same as 6:45 am |
12:00 am | Midnight — the start of the day |
12:00 pm | Noon |
Midnight and noon are the only two times where the 12-hour clock behaves the opposite way to instinct, and it is the reason 24-hour notation exists at all — the military time converter shows both sides of it.
For a length rather than a time of day, use the online timer; for winding down rather than being woken, the sleep timer ends in darkness instead of a sound. If the alarm is really a deadline in a shared room, the countdown timer shows the time remaining rather than only announcing the end.
Frequently asked questions
Will it ring if I close the laptop lid?
No. Closing the lid suspends the machine, which stops the page running altogether, and a suspended computer has no way to sound an alarm scheduled by a browser tab. The alarm resumes as a missed one when you open it again. If a laptop must ring, set it not to sleep on lid close, or use the operating system’s own alarm — on Windows that is the Clock app, on macOS a calendar alert with a sound.
Does it work if the tab is in the background?
Yes, and this is the part most pages get wrong. The tone is scheduled into the audio clock when you set the alarm, so the sound is already booked and does not depend on the page being awake to trigger it. Pages that create their sound at the moment of ringing find themselves frozen and silent, which is why so many browser alarms are quietly unreliable.
Why does the site ask for notification permission?
So that the alarm can also appear as a system notification, which is the thing you will actually see if the browser is behind other windows. It is asked for only when an alarm is set, never when the page opens, and refusing it costs you the notification and nothing else — the sound and the tab title still work.
Can I set an alarm for tomorrow?
Any time you enter that has already passed today is taken as tomorrow, which covers the usual case. Beyond that, an alarm needs the tab open the whole time, so a two-day alarm is not a realistic thing for a web page to offer. For anything further out, an email reminder is the honest mechanism, and the site offers one at the bottom of every page.
How this works
Sources:
The honest limits
Open tab, awake device. Those two conditions are the whole contract. Everything else about a browser alarm is detail.
Scheduled, not triggered. The distinction is why this one sounds from the background and many do not.
Nothing is stored. The alarm lives in the address bar, so a bookmark can carry a regular one — and nothing about your routine is kept on a server.