⏰ Alarm Clock

Set an alarm and get an audio alert right in your browser.

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This free online alarm clock runs entirely in your browser. Set the time, choose a sound and click Set Alarm. Keep the tab open and the alarm will play at the set time. Works on desktop and mobile — no download or app needed.

How to use the online alarm clock

Type a target time in the time picker (24-hour or AM/PM depending on your locale), give the alarm an optional label like "Stand up" or "Take pasta off", choose a sound — gentle chime, plain beep or loud — and adjust the volume slider. Click Set Alarm. The status bar confirms it. Add as many alarms as you like; they all queue in the upcoming list. When the time arrives, an alert card appears with Dismiss and Snooze (5 minutes) buttons. Keep the tab open and your speakers on.

How browser alarms actually work

There's no magic — JavaScript runs a clock loop checking the current time once per second. When hour and minute match a stored alarm, the Web Audio API generates the chosen sound on the fly using oscillators (no audio files to download). Browsers throttle background tabs to save battery, so a backgrounded tab may fire a few seconds late but will still fire as long as the tab exists. Closing the tab destroys the queue.

Frequently Asked Questions

Does the tab need to stay open?
Yes — the alarm runs in your browser tab, so it must stay open (but can be in the background). If you close the tab, the alarm will not fire. For phone alarms, use your device's built-in clock app.
Why didn't the alarm sound?
Browsers require a user interaction (like clicking a button) before playing audio. If you set the alarm without clicking anything first, the sound may be blocked. Try clicking the Set Alarm button, then wait for it to fire.
Can I set multiple alarms?
Yes — set multiple alarms in a row and they all appear in the Upcoming Alarms list below the clock.
Will it wake me up if my phone is locked?
Probably not reliably. iOS and Android suspend background browser audio. For sleep alarms, use your phone's native clock app. Browser alarms are best for short-term reminders while you're at the computer.
Can I label alarms?
Yes — the optional label appears in the upcoming list and on the ringing card so you remember what each alarm is for.

Tips for reliable browser alarms

Click any button on the page first so the browser permits audio playback. Pin the tab so you don't close it by accident. On laptops, disable "sleep on lid close" if you need an alarm overnight. For loud wake-ups, the "loud" sound profile uses alternating high frequencies that cut through ambient noise better than a single beep.

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