Pick a wake-up time that lands between sleep cycles
Most people wake up groggy not because they slept too little, but because the alarm went off in the middle of deep sleep. A night of sleep runs in cycles of roughly 90 minutes (it varies from about 80 to 110 minutes between people), and waking near the end of a cycle usually feels easier than waking in the middle of one.
| In bed at | 4 cycles (6 h) | 5 cycles (7.5 h) | 6 cycles (9 h) |
|---|---|---|---|
| 9:30 PM | 3:45 AM | 5:15 AM | 6:45 AM |
| 10:00 PM | 4:15 AM | 5:45 AM | 7:15 AM |
| 10:30 PM | 4:45 AM | 6:15 AM | 7:45 AM |
| 11:00 PM | 5:15 AM | 6:45 AM | 8:15 AM |
| 11:30 PM | 5:45 AM | 7:15 AM | 8:45 AM |
| 12:00 AM | 6:15 AM | 7:45 AM | 9:15 AM |
For a daytime power nap, the usual advice is the opposite: keep it short (about 20 minutes) so you wake up before deep sleep starts. The timer is the quicker tool for that, because you set a duration instead of a clock time.
How to set the alarm
- Check the big clock at the top. That is your device’s time, and the alarm follows it.
- Choose the hour and minute, or tap one of the quick picks (5:00 AM to 8:30 AM).
- Pick a sound and press Test to hear it at the current volume.
- Add a label if you like (“Morning run”, “School pickup”) and press Set alarm.
- When it rings, press Stop, or Snooze to hear it again a few minutes later.
Checklist for a reliable wake-up
- Keep the laptop plugged in with the lid open. A sleeping computer cannot play sound.
- Turn the system volume up and press Test once before bed; check that the tab is not muted.
- While an alarm is active, the page asks supporting browsers to keep the screen on.
- Open settings (gear icon) to change the snooze length, the volume or the auto-stop time.
Use your PC or laptop as an alarm clock
No phone in the bedroom? Any Windows PC, Mac, Chromebook or Linux laptop can be your alarm clock: open this page, set the time and leave the tab open. Four quick checks make sure the PC alarm really rings in the morning.
| System | Setting |
|---|---|
| Windows 11 | Settings → System → Power & battery → Screen, sleep & hibernate timeouts → sleep: Never |
| macOS | System Settings → Battery → Options → Prevent automatic sleeping on power adapter when the display is off |
| Chromebook | Settings → Device → Power → while charging: Keep display on |
| Linux (GNOME) | Settings → Power → Automatic Suspend off |
In Chrome or Edge, the memory saver may put an unused tab to sleep. Add this site to “Always keep these sites active” (Settings → Performance) if you set alarms many hours ahead.
Set an alarm for any o’clock
Tap a time below and the alarm opens ready to go: check the sound and press Set alarm.
| Morning | On the hour | Half past |
|---|---|---|
| 5 o’clock | 5:00 AM | 5:30 AM |
| 6 o’clock | 6:00 AM | 6:30 AM |
| 7 o’clock | 7:00 AM | 7:30 AM |
| 8 o’clock | 8:00 AM | 8:30 AM |
| 9 o’clock | 9:00 AM | 9:30 AM |
Need an alarm in 10, 20 or 30 minutes rather than at a clock time? The timer is quicker: you enter a duration instead.
A free alarm clock without the extras you don’t want
- Free, with no sign-up: no account, no email, nothing to install.
- Loud when you need it: 10 built-in sounds, from a soft chime to a buzzer and a siren, with a volume control in settings.
- As many alarms as you like: each with its own label and sound, all in one tab.
- Still there after a reload: alarms are saved in your browser, not on our servers.
- Works offline: once the page has loaded, the alarm rings even if the Wi-Fi drops.
Daylight saving time and your alarm
The alarm uses your operating system’s clock, so it follows clock changes automatically. In the US, clocks went back on Sunday, November 1, 2026 and go forward again on March 14, 2027. In the UK they went back on October 25, 2026 and go forward on March 28, 2027. If an alarm is set for the night of a change, the 2 AM hour that repeats or is skipped can make the “rings in” countdown look an hour off. The ring time itself stays correct.
In the Philippines, India and most of Asia there is no daylight saving time at all, so the alarm time never moves.
Frequently asked questions
Will the alarm ring if I switch to another tab?
Yes. The tab only has to stay open, not visible. You can keep working in other tabs or apps.
Does it work if my computer goes to sleep?
No. When the computer sleeps or the laptop lid closes, the browser pauses and cannot play sound. Keep the device awake and plugged in.
Can I set more than one alarm?
Yes. Every press of Set alarm adds another alarm to the list, each with its own label and sound.
Do I need an internet connection?
Only to load the page. Once it is open, the alarm still rings if your Wi-Fi drops.
Why did the alarm ring without sound?
Browsers keep a page silent until you click or tap it. This happens when the tab was reopened or reloaded after you set the alarm, for example after the computer slept. Click anywhere on the page once (a bar at the bottom reminds you), make sure the tab is not muted, and press Test.
Can I use my PC as an alarm clock?
Yes. Open this page on any Windows PC, Mac, Chromebook or Linux computer, set the time and leave the tab open. Keep the computer plugged in and stop it from going to sleep.
Is this alarm clock really free?
Yes, completely. There is no account, no paid version and nothing to download.
How do I set an alarm for 7 o’clock?
Choose 7 in the hour list and 00 in the minutes, or use the 7:00 AM link in the table above, then press Set alarm.
How long should a nap alarm be?
For a quick refresh, about 20 minutes. A full 90-minute cycle also works, but anything in between often lands in deep sleep and leaves you groggy.
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