Set visual/audio alarms and reminders in your browser.
Utility
ADDITIONAL INFORMATION
This online alarm clock runs in your browser, needs no download, no account, and no app. Pick a time, choose a sound, and leave the tab open — it will ring. Most people are here because their phone is dead, in another room, or deliberately out of reach, and they need something set in the next five seconds.
The alarm above handles that. The guide below handles the part almost every other alarm site ignores: making sure it actually goes off.
Set the time, pick a sound, press start. That's the whole flow.
That's it. The alarm runs against your device's own clock, so it generally keeps working if your internet connection drops after the page has loaded. If you would rather count forward — “wake me in 20 minutes” — use the Countdown Timer.
An online alarm clock is a small program running inside your browser tab that watches your device's clock and triggers a sound when the target time arrives. It is not a service running on a distant server that phones you at the right moment — and that distinction explains every important limitation.
Because the alarm runs locally, it can continue after Wi-Fi drops. Reloading the page while offline is different: the page must already be loaded before the connection is lost.
Closing the tab kills the alarm. Locking the screen is usually fine. Letting the device sleep is not. These three things are often confused, so treat them separately.
Mobile browsers are especially aggressive about suspending background tabs to save battery, so a browser alarm on a phone is unreliable overnight. For a flight, exam, job interview, or medication, set a phone alarm as a backup. No web page can override a sleeping device.
Run through this list once and your alarm is much more likely to fire. Skipping the first item is a common cause of silent alarms.
All three measure time, but the right tool depends on what you know at the start:
| You want to… | Use | Example |
|---|---|---|
| Ring at a specific clock time | Alarm clock | Wake at 6:30 AM or leave for a meeting at 2:15 PM |
| Ring after a set duration | Countdown Timer | Nap for 20 minutes or boil eggs for 7 minutes |
| Measure how long something takes | Stopwatch | Time a run or track a task |
The quick test: if you are thinking of a time on the clock, use the alarm. If you are thinking of a number of minutes from now, use a Countdown Timer. If you want to find out how long something takes, use a Stopwatch.
If you have a fixed obligation, work backwards from it and add slack for the things that always take longer than expected. To calculate the time between now and a deadline, use the Time Calculator.
If your wake time is flexible, sleep structure is worth considering — with a caveat about precision. Sleep moves through light sleep, deep sleep, and REM in repeating cycles commonly described as roughly 90 minutes. That is an average, not a personal timer: cycle lengths vary between people and across a single night.
Waking during deep sleep can produce sleep inertia — the heavy, disoriented grogginess that lingers after the alarm. This is why 7.5 hours can sometimes feel better than 8 hours. But setting alarms at exact 90-minute multiples treats an average as a precision instrument. You cannot know exactly when you will fall asleep or how stress changes your sleep stages.
Use 90-minute multiples only as a rough tiebreaker between two reasonable wake times. Total sleep and a consistent schedule matter more. Adults generally need seven to nine hours, and a regular routine supports your circadian rhythm better than an alarm-timing trick.
For a nap, 10 to 20 minutes is usually practical. Beyond about 30 minutes, you increase the chance of waking from deeper sleep and feeling worse than before you lay down.
Snooze delays an alarm by a short interval, typically five to ten minutes, and feels like a small mercy. Used repeatedly, it works against you: each snooze starts sleep you do not have time to finish, then interrupts it again.
Set the alarm for when you actually need to get up instead of setting it 30 minutes early with several snoozes budgeted in. Put the device out of arm's reach so standing up does some of the waking. If you are a heavy sleeper, a single loud alarm you must cross the room to silence is more useful than a gentle one you can dismiss without waking fully.
This alarm uses your device's local time — the same clock shown in your taskbar or menu bar. Set it for 7:00 AM and it rings at 7:00 AM according to that local clock.
When travelling, your laptop may update its time zone automatically after connecting in a new location. An alarm set before you travel can therefore shift relative to local time. After crossing time zones, re-check every active alarm. To compare a time elsewhere, use the Time Zone Converter.
Daylight saving transitions need extra care. When clocks go forward, an hour does not exist; when clocks go back, an hour occurs twice. For an alarm spanning either transition, set a phone alarm as well because native alarm apps handle these edge cases more predictably.
An audio-only alarm excludes people who are deaf or hard of hearing and can fail in a shared or noisy space. A visual alert — such as a flashing or colour-changing page — can provide a second channel, while phones and tablets may offer vibration.
Dedicated bed-shaker alarms under a pillow or mattress are the reliable solution when audio alarms are not enough. For low-vision users, a large high-contrast clock display and keyboard operation matter more than tone selection. Test any alarm once under real conditions before trusting it.
Work down this table in order. The first two rows account for many silent alarms.
| Symptom | Likely cause | Fix |
|---|---|---|
| Alarm time passed with no sound | Browser blocked audio through autoplay policy | Click the page, play the sound once, then set the alarm again |
| No sound but the alarm triggered | System muted or audio routed to headphones | Check volume and output device |
| Nothing happened and the tab was gone | Tab closed or browser restarted | Set it again and pin the tab |
| Alarm fired late | Device slept or suspended | Prevent sleep and keep the charger connected |
| Phone alarm failed overnight | Mobile browser suspended the tab | Use the phone's native alarm app |
| Notification was silent | Do Not Disturb or Focus mode | Disable it or add a browser exception |
| Alarm rang at the wrong time | System clock, time zone, or DST shift | Enable automatic time sync and re-check after travelling |
| Alarm is inconsistent | Battery saver throttled background activity | Turn off low-power mode and plug in |
If an alarm has failed once, treat that device as untrustworthy for critical alarms until you identify which row applied.
Scroll back up, set the time, and play the sound once to make sure your browser will let it through. Leave the tab open, keep your device from sleeping, and this online alarm clock will do its job. If you are setting it for a flight, an exam, medication, or anything you cannot afford to miss, set a phone alarm too.
Working with times and dates elsewhere? The Countdown Timer, Stopwatch, and Time Zone Converter cover the rest of the Date & Time toolkit.
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