Online Alarm Clock
Set an alarm that will play a sound at the specified time.
Current Time
01:23:46
Note: This is a simple browser-based alarm and may not be reliable for critical alerts.
How to set an online alarm clock
Enter the time you want the alarm to go off (in 12-hour format with AM/PM), then click Set Alarm. The alarm will fire when your device's clock reaches the specified time. A countdown timer shows exactly how long until the alarm triggers. The alarm sound plays through your browser's audio system — make sure your device volume is turned up and the tab is still open when the time comes.
Important limitations
This alarm runs in your web browser, which means it only works while the browser tab is open and your device is on. If you close the tab, put your device to sleep, or navigate away from the page, the alarm will not fire. For critical alarms (like waking up for a flight), always use your phone's native alarm app as a backup. Browser-based alarms are best suited for desk work, study sessions, cooking reminders, and other activities where you're already in front of a screen.
How the alarm sound works
When the alarm triggers, the page plays an audio file using the HTML5 Audio API. Modern browsers require a user interaction (like clicking the "Set Alarm" button) before allowing audio playback — this is a security feature to prevent websites from playing unexpected sounds. The alarm audio file is preloaded when you set the alarm, so it plays immediately when the time arrives without any network delay.
Common uses for an online alarm
- Study sessions: Set an alarm to remind yourself to take a break after a focused study period.
- Cooking reminders: Set an alarm for when your food is done — the sound plays through your speakers even if you're in another room.
- Meeting alerts: Set a 5-minute warning before an important call so you have time to prepare.
- Medication timing: Set alarms for daily medication schedules (always use a backup method for health-critical timing).
- Workout rest periods: Set a short alarm to signal when your rest period between sets is over.
- Nap timer: Set an alarm for a 20-minute power nap at your desk.
Related tools
- Countdown Timer — count down from a set duration.
- Online Stopwatch — measure elapsed time with laps.
- World Clock — see the current time worldwide.
- Meeting Planner — schedule across timezones.
Related Resources
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Frequently Asked Questions
An Online Alarm Clock is a free browser-based tool that plays a loud alarm sound at a specific time you set. It works on your computer, laptop, or mobile device without needing to install any app or software.
Simply use the time input field to select the hour and minute you want the alarm to go off. Then, click the 'Set Alarm' button. A confirmation message will appear, and the countdown to your alarm will begin.
No. For the alarm to function, this browser tab must remain open. If you close the tab or your computer goes into sleep mode, the alarm will not work.
Currently, our Online Alarm Clock uses a standard, pre-selected alarm sound to ensure reliability. We do not support custom sounds at this time.
No. The alarm plays a sound through your device's audio output. If your computer's volume is muted or set to zero, you will not hear the alarm.
Our current version does not feature a snooze button. To turn off the alarm, you must click the 'Stop Alarm' button. This is designed to help ensure you get up.
At the set time, a loud alarm sound will start playing, and the screen will display an 'ALARMING!' message. The sound will continue to play in a loop until you click the 'Stop Alarm' button.
This is a simple browser-based alarm. While it is a great tool for reminders, naps, or as a backup, we do not recommend relying on it for critical appointments, as its function depends on your browser and computer staying active.
Yes, it works on most modern mobile browsers. However, similar to a desktop, the browser tab must remain open and your phone must not be in silent mode for the alarm to sound.
Yes, the time input uses the 24-hour format (HH:MM) to avoid confusion between AM and PM. For example, to set an alarm for 1:30 PM, you would enter '13:30'.
Yes, the alarm clock automatically uses your computer's system time. Whatever time your device's clock shows is the time the alarm clock will be synced to.
This tool is designed to manage one alarm at a time. To set a new alarm, you must first cancel or stop the current one.
Yes, our Online Alarm Clock is completely free to use. There are no hidden charges or subscriptions.
The most common reasons are: the browser tab was closed, the computer was in sleep mode, the device's volume was muted, or browser permissions prevented the audio from playing automatically.
It's perfect for timing tasks at work (like the Pomodoro Technique), setting reminders to take a break, using as a kitchen timer for cooking, or for a quick power nap.
You need an internet connection to load the page initially. However, once the page is loaded, the alarm logic runs in your browser and does not require a constant internet connection to function.
If you have an alarm scheduled, a 'Cancel Alarm' button will be visible. Simply click this button to deactivate the alarm before it goes off.
Yes. The alarm time you set is stored only in your local browser and is not sent to our servers. We do not track or store any personal data.
The alarm volume is controlled by your computer's main volume setting. You can adjust your system volume to make the alarm louder or quieter.
First, check that your device volume is not muted. Second, some browsers may block automatic audio playback. Ensure you have given our site permission to play audio if prompted.