Online alarm clock: set your alarm in seconds
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Your Alarms
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What is an online alarm?
An online alarm is an alarm clock that works directly in your web browser, without installing any app, extension, or program. You open the page, choose the time you want it to ring, and the browser handles everything. It's the fastest way to set an alarm: zero setup, zero unnecessary permissions, zero disk space.
At AlarmClock24 we've built the most complete online alarm clock. You can set multiple alarms at once, each with its own label and sound, snooze them, test sounds before using them, and everything works even if you switch tabs or minimize the browser.
How to use AlarmClock24
- Pick the time: use the hour and minute fields in the widget above, or click a quick preset (6:00, 7:00, 7:30…).
- Optional label: type a label to identify your alarm ("Work", "Medication", "Pick up kids"…).
- Pick a sound: choose from several alarm sounds and test each one with the "Test sound" button.
- Click "Set alarm": the alarm appears in your active alarms list with a countdown until it rings.
- When it rings: you can dismiss it or snooze it for 1, 5, 10, or 15 minutes.
You can also bookmark a URL with a pre-filled time: add ?t=07:30 to the URL
and save it for one-click alarm setting.
Honest compatibility
Here's what AlarmClock24 can and cannot do on each platform. We prefer being honest over promising the impossible.
| Situation | Windows / Mac / Linux | Android | iOS |
|---|---|---|---|
| Tab open & visible | ✅ Works | ✅ Works | ✅ Works |
| Tab in background | ✅ Works | ✅ Works | ⚠️ Limited audio |
| Screen locked | ✅ Works with Wake Lock | ⚠️ Device-dependent | ❌ Not reliable |
| Device suspended | ❌ Doesn't work | ❌ Doesn't work | ❌ Doesn't work |
| Push notifications | ✅ | ✅ | ❌ Not supported on iOS |
| Offline (already loaded) | ✅ | ✅ | ✅ |
Updated: July 2026. Browsers and OSes change; this table reflects current behavior on Chrome, Firefox, Safari, and Edge.
Use cases
- Daily wake-up: set your alarm to get up every morning. With Wake Lock active, your screen won't turn off overnight.
- Naps: use a quick 20 or 30-minute alarm for a power nap without oversleeping.
- Medication: label your alarms with the medicine name and dosage. Ideal for people who need reminders at fixed times.
- Work & productivity: Pomodoro technique with the timer, or alarms for meetings and breaks.
- Cooking: baking something that needs to come out at an exact time? Set the alarm and carry on. We also have a dedicated egg timer.
- Picking up kids: thousands of parents use AlarmClock24 to remember school and after-school pickup times.
- Travel & time zones: check the world clock and set alarms for video calls in other time zones.
More time tools
AlarmClock24 is more than just an alarm. You also have at your disposal:
- Online timer — countdown with presets and Pomodoro.
- Online stopwatch — millisecond precision with laps.
- Fullscreen clock — keep the time visible during long sessions.
- World clock — check the time in any city worldwide.
- Egg timer — perfect timing for soft, medium, or hard-boiled eggs.
Frequently asked questions
Does the alarm ring if I close the tab or browser?
No. The alarm needs the AlarmClock24 tab to stay open in your browser. If you close the tab or the browser, the alarm won't ring. You can minimize the tab or switch to another one, but don't close it. Browser notifications are a useful complement, but they still depend on the tab staying open in the background.
Does it work with the computer off or suspended?
No. Like any online alarm, AlarmClock24 needs the device to be on and the browser tab open to ring. If the computer goes to sleep or shuts down, the alarm won't ring. The Wake Lock feature helps prevent the device from sleeping while an alarm is set, but not all browsers support it.
Is AlarmClock24 free?
Yes, AlarmClock24 is completely free. There are no paid plans, subscriptions, or premium features. All tools — alarm, timer, stopwatch, clock, world clock, and egg timer — are available at no cost. The site is supported by non-intrusive advertising.
Do I need to download or install anything?
No. AlarmClock24 works directly in your browser (Chrome, Firefox, Safari, Edge). No app or extension needed. Just open the website, set the time, and you're done.
Does it work on iPhone or iPad?
Yes, with limitations. In iOS Safari, autoplay blocking prevents audio from playing unless you've interacted with the page first. We recommend clicking 'Test sound' when setting the alarm to unlock audio. Also, iOS doesn't support Wake Lock, so the screen may turn off. If the iPhone locks, the alarm won't ring until you unlock and return to the tab. For serious wake-up use on iPhone, we recommend the native Clock app.
Can I set multiple alarms at once?
Yes, you can set as many alarms as you need. Each one can have its own label, sound, and time. The 'Your alarms' list shows all active alarms and lets you enable, disable, or delete them individually.
Does it work offline?
Yes. Once the page has loaded, the alarm works completely offline. The clock uses your device's local time and sounds are generated with the Web Audio API. No internet connection is needed for the alarm to ring — you only need a connection to load the page initially.
How loud is the alarm?
The alarm volume depends on your device and browser volume. Make sure the system volume and tab aren't muted. The alarm uses a progressive volume (ramps up over 20 seconds) for a gentler wake-up. You can test each sound before setting the alarm with the 'Test sound' button.
What is an online alarm?
An online alarm is an alarm clock that works directly in your browser, without installing any app.
What's the difference between the alarm and the timer?
The alarm rings at a specific time of day (e.g., 7:30 AM). The timer counts down from a duration you choose (e.g., 25 minutes) and rings when it reaches zero. Use the alarm to wake up or remember a fixed time; use the timer for cooking, studying with Pomodoro, or any task with a set duration.