World Clock, Timer, Stopwatch & Alarm
Four essential time tools — auto-detects your timezone
Monday, January 1, 2024
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Online Clock, Timer, Stopwatch & Alarm — All in One
Calculator Junction's time tools combine four essential utilities in a single, clean interface. Whether you need to track elapsed time with the stopwatch, count down to an event, set a morning alarm, or simply check the current time in any timezone — everything is here, free, and requires no download.
The world clock automatically detects your timezone using your browser's built-in locale API — no location permission required. Switch to any of the 400+ IANA timezones grouped by continent using the dropdown. The alarm clock generates a clear chime via the Web Audio API, the countdown timer shows a live SVG progress ring, and the stopwatch records laps with split and cumulative times.
World Clock
- ›Auto-detects your system timezone on load
- ›Toggle between 12-hour and 24-hour formats
- ›400+ IANA timezones grouped by continent
- ›Updates in real time — every second
Alarm Clock
- ›Set multiple alarms with custom labels
- ›Optional daily repeat toggle
- ›Audio chime via browser Web Audio API
- ›Keep the tab open and browser unmuted
Countdown Timer
- ›Set hours, minutes, and seconds
- ›Quick presets: 1, 5, 10, 15, 30 min, 1 hr
- ›Live SVG ring shows remaining time visually
- ›Ascending chime alert when countdown ends
Stopwatch
- ›Millisecond-precision display (HH:MM:SS.mmm)
- ›Tap Lap to record split and total times
- ›Laps listed newest-first for quick reading
- ›Pause, resume, and reset at any time
Frequently Asked Questions
Does the online alarm clock actually ring?
Yes — it uses the browser's Web Audio API to synthesise a chime at the set time. Keep the browser tab open and the tab not muted. No external sound files are needed; audio is generated client-side.
Why does the clock show the wrong time?
The clock reads your device's system clock and timezone. If the time is incorrect, check your OS date & time settings. You can also manually select the correct timezone from the dropdown in the Clock tab.
How accurate is the stopwatch?
The stopwatch uses performance.now() for sub-millisecond resolution. Browser tab-throttling may reduce accuracy if the tab is in the background — keep it active for precise measurements.
Which timezones are supported?
All IANA timezone entries — over 400 named zones covering every country — are available via the dropdown, grouped by continent. Popular zones like India (IST, GMT+5:30) and UTC appear at the top for quick access.
How does fullscreen mode work?
Click the fullscreen icon (⤢) next to the tab bar. The tool card expands to fill your entire screen — perfect for a desk clock or timer display. Press Esc or click the icon again to exit.