Free Online Alarm Clock, Timer & World Clock

Set an alarm, start a timer or check the time anywhere in the world. No signup, no app, no download. Open it, use it, close it.

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Your local time

Set an Alarm Start a Timer

Alarm Clock

Set one or many alarms with custom labels. Persists across sessions.

Countdown Timer

Set any duration or pick a preset (1, 5, 10, 15, 30, 60 min).

Stopwatch

Centisecond precision. Lap times with best/worst highlighted.

World Clock

Live time, sunrise and sunset in 80+ cities.

Sleep Calculator

Best bedtime for your alarm, based on 90-minute sleep cycles.

World clock — popular cities right now

Live local time in major cities around the world. Click any card for sunrise, sunset, business hours and more.

United Kingdom · GMT/BST

France · CET/CEST

Germany · CET/CEST

Singapore · SGT

Hong Kong · HKT

Australia · AEST/AEDT

See all cities →

Why iAlarmClock?

🚀

Loads instantly

Plain HTML and a few KB of JavaScript. No framework, no pop-ups, no waiting.

🔒

Private by design

Everything runs in your browser. Your alarms never leave your device.

📴

Works offline

After your first visit, the app is cached. Use it on a plane.

📲

Add to home screen

Install as a Progressive Web App for one-tap access from your phone.

🎯

No signup, ever

No accounts, no email, no permissions you don't actually need.

🌗

Light & dark

Automatically matches your system theme. Easy on the eyes day and night.

Set an alarm in one click

The most popular wake-up times. Each page also shows the best bedtime for that alarm.

4:00 AM 4:30 AM 5:00 AM 5:30 AM 6:00 AM 6:30 AM 7:00 AM 7:30 AM 8:00 AM 8:30 AM 9:00 AM 9:30 AM

All alarm times →

Popular timer presets

One-click countdowns for the durations people use most.

1 minute

Quick countdown.

5 minutes

Steeping tea, short break.

10 minutes

Power nap, focus burst.

15 minutes

Coffee break.

20 minutes

Pomodoro session.

25 minutes

Classic Pomodoro.

30 minutes

Cooking, study sprint.

45 minutes

Deep work block.

1 hour

Workout, meeting limit.

Frequently asked questions

Will the alarm ring if I switch tabs or lock my phone?

The alarm uses your browser's audio engine, so it will ring as long as the tab stays open. To make sure it sounds even with the screen off, keep the tab unmuted, allow notifications, and keep the device plugged in. Browsers may suspend background audio after long idle periods — for critical wake-ups always set a phone alarm as backup.

Is iAlarmClock really free?

Yes. 100% free, no signup, no email required, no download. Just open the page.

Do I need to install anything?

No. It runs in any modern browser. You can optionally "Add to home screen" to install it as a Progressive Web App for one-tap access.

Are my alarms saved if I close the tab?

Yes. Alarms are stored locally in your browser. They'll be there next time you visit on the same device and browser. Nothing is sent to a server.

Can I use it offline?

Yes. After your first visit, a service worker caches the app so it works without an internet connection.

What time zones does the world clock support?

All IANA time zones via your browser's built-in Intl API. We have dedicated pages for more than 80 cities, each with the live time, UTC offset, daylight saving dates and sunrise/sunset times.