Free Online Alarm Clock — No Download Required
OnlineTimeZone delivers a premium browser-based alarm clock that works entirely offline once loaded. Powered by the Web Audio API, your alarms synthesize sound directly in your browser — no MP3 files, no server dependency, no app installation. Set multiple alarms, snooze, dismiss, and customize the sound and volume to suit your needs.
Frequently Asked Questions — Online Alarm Clock
Yes, completely. Once OnlineTimeZone has loaded in your browser, the alarm system runs 100% offline. All alarm sounds are synthesized locally using the Web Audio API — there are no external audio files to fetch, so even if your WiFi disconnects, your alarms will still ring on schedule.
Yes, the alarm will still trigger as long as the tab remains open in your browser. Modern browsers continue running JavaScript timers in background tabs. However, some aggressive battery-saving modes on mobile devices may throttle background tabs, so we recommend keeping the tab visible for critical wake-up alarms.
Absolutely. You can add as many alarms as you need — simply select a new time and click "Add Alarm" repeatedly. All active alarms appear in the list sorted chronologically. The browser tab title also updates to show your next upcoming alarm time so you always know what is scheduled at a glance.
When your alarm rings, you can snooze it for 1, 5, 10, 15, 30, or 60 minutes — configurable in Settings. The snooze duration shifts the alarm forward by your chosen interval and re-enables it automatically. You can change your default snooze duration at any time in the Settings panel.
OnlineTimeZone offers three synthesized alarm sounds: a soft Chime, a sharp Digital Beep, and an urgent Siren Alert. All sounds are generated in real-time by the Web Audio API — no sound files are downloaded. You can also adjust the alarm volume from 0 to 100 using the volume slider in Settings, and toggle looping so the alarm repeats until dismissed.