How to set an online alarm
- Pick the time. Type it into the time field or use the stepper. The field follows your device's convention, so it will show AM/PM or a 24-hour value depending on your regional settings.
- Add a title (optional). The title appears on screen when the alarm fires, which matters if you have several alarms queued — "Take medication" is a great deal clearer than a bare time.
- Choose a sound. Classic Ring is the loudest and hardest to sleep through; Digital Beep is sharp and cuts through background noise; Bell is warmer; Soft is deliberately gentle for a nap or a discreet reminder in a shared room. Use Test Sound to check the volume before you rely on it.
- Set repeat days (optional). Tap the day chips to make the alarm recur on those weekdays only — Mon–Fri for a work routine, for example. Leaving every day unselected means the alarm rings every day.
- Press "Set Alarm". It joins the list below and stays there, saved on this device, until you delete it.
When the alarm fires, a full-screen panel appears with your title and the time. You can stop it outright or hit Snooze 5 min, which re-arms the same alarm five minutes later — the standard snooze interval used by almost every alarm clock since the 1950s, when the mechanical gearing of the first snooze alarms made roughly nine minutes the practical minimum.
Before you rely on it: how browser alarms actually behave
An alarm that runs inside a web page is not the same thing as the alarm app built into your phone, and it is worth understanding the difference before you trust it with an early flight.
- The tab has to stay open. Closing the tab, quitting the browser or restarting the device ends the countdown. The alarm is stored, but nothing is running to trigger it.
- The device has to stay awake. If the machine sleeps or hibernates, the browser is suspended along with everything else. Disable sleep, or keep the device plugged in with the screen timeout extended.
- Sound needs one interaction first. Browsers block audio on pages the user has never interacted with, to stop sites from blaring at you unprompted. Pressing Test Sound once satisfies this requirement for the rest of the session.
- Silent mode still wins. A muted device, a muted browser tab, or headphones plugged into a socket you are not wearing will all silence the alarm. Check the output before you go to sleep.
For anything genuinely critical — catching a flight, an exam, medication — set a backup on your phone's native alarm app as well. A browser alarm is excellent for a nap, a laundry cycle, a meeting reminder or a reminder to stand up; it is not a safety-critical device.
What people use it for
- Working at a desk all day. An alarm at a fixed hour is a reliable prompt to stop, stretch or leave on time — more effective than a calendar notification you have already learned to dismiss.
- Naps. A twenty-minute nap ends before deep sleep begins and leaves you alert; sleeping past roughly thirty minutes tends to produce grogginess instead. Use the 20-minute timer if you want a countdown rather than a clock time.
- Medication and hydration reminders on a repeating weekday schedule.
- Shared and public machines where installing anything is not an option — the alarm needs nothing but a browser tab.
- Waking up on a borrowed device in a hotel or at a friend's place.
Where your alarms are stored
Alarms live in your browser's local storage on this device only. They are never uploaded, so there is no account to create and nothing for us to see. The flip side is that they do not follow you: an alarm set on your laptop will not ring on your phone, clearing your browser data deletes them, and a private or incognito window forgets them as soon as you close it.
Frequently Asked Questions
Will the alarm ring if my computer goes to sleep?
No. A sleeping or powered-off device suspends the browser, so nothing can fire. Keep the device awake and the tab open — adjust the sleep and screen-timeout settings in your operating system if necessary.
Will it ring if the tab is in the background?
Usually yes, as long as the browser is still running and the tab has not been discarded to save memory. Background tabs are throttled by every modern browser, so the alarm may fire a few seconds late. Keeping the tab visible is the reliable option.
Why can't I hear anything?
Work through the usual suspects: press Test Sound to grant audio permission, check that the tab is not muted (right-click the tab to see), check the system volume, and confirm the audio is not being routed to a disconnected speaker or headset.
Are my alarms saved when I close the page?
The alarms themselves are saved on this device and will be there when you return. They do not run while the page is closed, though — reopen the page to arm them again.
Can I set more than one alarm?
Yes, add as many as you like. Each one keeps its own time, title, sound and repeat days, and they appear together in the list.
How do I delete an alarm?
Use the delete control on the alarm's row in the list below the form.
Does it work on a phone?
It does, but mobile browsers are aggressive about suspending background tabs to save battery. On a phone, your built-in alarm app is the more dependable choice.
Related tools
If you want to count down a duration rather than wake at a specific time, use the timer — there are one-click presets from 1 minute to 12 hours. For measuring elapsed time there is the stopwatch, and for counting down to a date there is the countdown.