What is an Online Alarm Clock?
An online alarm clock is a free alarm service that works directly in your web browser without any app installation. You can easily set and manage alarms on any device with an internet connection — PC, laptop, tablet, or smartphone.
Choose from 15 sounds, add up to 10 alarms, snooze and fill in times using quick presets. Added alarms are saved when browser storage is available. Draft entries that have not been added are not saved.
Key Features
Multiple Alarms
Set and manage up to 10 alarms simultaneously. Label each alarm to distinguish its purpose.
15 Alarm Sounds
Choose from 15 diverse alarm sounds including Soft Bells, Arpeggio, Swinging Jazz, Rooster, and more.
Quick Presets
The 10-minute, 30-minute, 1-hour and 2-hour buttons fill in the time and label. Check the values, then press Add Alarm to activate the alarm.
Snooze Function
When the alarm rings, press the snooze button to be reminded again in 5 minutes.
Browser Notifications
When the alarm page is still running and permission is granted, a browser notification appears with the sound. Hidden tabs can be delayed or suspended by the browser or operating system.
How to Use
- Step 1: Set Time — Enter the hour and minute using your device time, or fill the fields with a quick preset. Pressing a preset alone does not add an alarm.
- Step 2: Choose Sound — Select one of the 15 alarm sounds and preview it to confirm.
- Step 3: Add Alarm — Enter an optional label first, then press Add Alarm to activate it. Check that the alarm appears in the list.
- Step 4: Manage Alarm — When the alarm rings, choose 'Dismiss' or 'Snooze (5 min)' to respond.
Use Cases
Power Nap Alarm
Use quick presets to set a 10-30 minute alarm for a refreshing short nap.
Medication Reminder
Use labels as a supplementary medication reminder. For important doses, also use an operating-system alarm or the reminder method recommended by your clinician.
Cooking Timer
Set alarms matching cooking times so you never miss the perfect moment.
Meeting Reminder
Set alarms before important meetings or events to ensure you have preparation time.
Frequently Asked Questions (FAQ)
Will the alarm work if I close the tab?
No. The alarm is checked only while this page's tab remains open and the browser keeps it running. It can ring while you view another tab and can also show a notification when permission is granted, but sleep, screen lock and background-tab limits can delay or suppress both. Use an operating-system alarm as a backup for anything important.
What if the alarm sound doesn't play?
Preview the sound first. Check tab mute, device media volume, audio output such as Bluetooth headphones, and silent settings. The effects of silent mode and autoplay restrictions vary by device and browser; clicking the page once does not guarantee later playback. Also check that the alarm page is still running at the scheduled time.
Can I set multiple alarms?
Yes, you can set up to 10 alarms simultaneously. Each alarm can have different times, sounds, and labels for various purposes.
Are alarm settings saved?
Added alarms are saved when the browser’s localStorage is available. They are restored when you return on the same device and browser if the saved data remains. Blocking storage or deleting the data prevents this, and saved alarms do not run while the tab is closed.
Can I set alarms to repeat daily?
Only one-time alarms are supported. Dismissing an alarm disables it, so switch it back on manually when you want to reuse it. The page tab must be open at the scheduled time.
Sleep Cycles and Alarm Timing: What to Know
Sleep inertia is the temporary reduction in alertness and performance after waking. Its severity and duration can depend on prior sleep, biological timing, the stage before waking, the person and the task. A fixed 90-minute calculation cannot control all of those factors, so adequate total sleep and a regular schedule are more practical priorities.
The American Academy of Sleep Medicine and Sleep Research Society recommend that healthy adults regularly obtain at least seven hours of sleep, while individual needs and circumstances can differ. The arithmetic table below is illustrative, not medical guidance or a prediction of sleep stages. Seek medical advice for persistent insomnia, severe daytime sleepiness or difficulty waking.
The Psychology of Alarm Sounds
A 2020 PLOS ONE study from RMIT surveyed participants about their usual waking sound and self-reported sleep inertia. Sound type itself was not significantly associated with sleep inertia; sounds participants rated as more melodic were associated with lower reported inertia. It was an observational survey, not a cognitive performance test proving causation or a cortisol mechanism.
Specific frequencies, tempos and sound categories therefore should not be treated as universal prescriptions. Clock-Tani's 15 sounds play at a steady volume; it has no gradual-volume feature. Preview the selected sound on the device you will use, then check the tab mute state, media volume and Bluetooth output. Do not rely on a browser alarm alone for an important wake-up.
90-Minute Time-Addition Examples
The table below simply adds four, five or six 90-minute blocks to an assumed time of falling asleep. Sleep cycles are not fixed at 90 minutes and a clock cannot determine your current sleep stage, so these results do not guarantee easier waking or prescribe a personal bedtime.
| Assumed sleep time | 5 cycles (7.5h) | 6 cycles (9h) | 4 blocks (6h example) |
|---|---|---|---|
| 21:00 | 04:30 | 06:00 | 03:00 |
| 22:00 | 05:30 | 07:00 | 04:00 |
| 22:30 | 06:00 | 07:30 | 04:30 |
| 23:00 | 06:30 | 08:00 | 05:00 |
| 23:30 | 07:00 | 08:30 | 05:30 |
| 24:00 | 07:30 | 09:00 | 06:00 |
| 00:30 | 08:00 | 09:30 | 06:30 |
| 01:00 | 08:30 | 10:00 | 07:00 |
This is a comparison of 90-minute multiples, not a recommendation to choose any column. Actual sleep onset and cycle lengths vary. Prioritize adequate total sleep and a consistent schedule; consult a clinician if sleep problems persist.
Privacy Notice
Added alarms and labels are kept in this device’s browser storage. If you consent to analytics cookies, an alarm-added event and the selected hour and minute may be sent to Google Analytics; the alarm label is not included in that event. Feedback text and an optional email address are sent through Google Forms. See the Privacy Policy for details.