1. What does this tool do
This free online clock gives you a world clock, stopwatch, and countdown timer in one place. Use it as a world clock to see live time across any IANA timezone, run a stopwatch with laps, or set a countdown—no app to install, no sign-up. Everything runs in your browser so it works on any device. Ideal for meetings, cooking, workouts, exams, or travel.
2. How to use it
Quick start: Add timezones to the world clock for live time, or switch to stopwatch/countdown. Start, lap, and read times—no sign-up.
- World clock — Add timezones (e.g. UTC, your city, a colleague’s). Time updates every second. Add or remove zones as needed.
- Stopwatch — Start, pause, resume, and record laps. Use it for timing tasks or exercises.
- Countdown — Set hours, minutes, seconds and start. The tool alerts or shows when time is up (depending on implementation).
- Switch tabs — Move between world clock, stopwatch, and countdown using the tool’s tabs or controls.
3. How it works
World clock uses the browser’s Date and timezone APIs (e.g. Intl, or fixed offsets for IANA zones). Stopwatch uses a timer (setInterval or requestAnimationFrame) to update elapsed time; laps are stored in memory. Countdown decrements a remaining value on a timer. All logic runs client-side in your browser. No data is sent to any server.
4. Use cases & examples
- Meetings and world clock — Check time in other offices with the world clock.
- Cooking or workouts — Use the stopwatch or countdown.
- Exams or focus — Set a countdown for a timed session.
- Travel — See local time for your destination before you go.
Example
- Add "America/New_York" and "Asia/Tokyo" to see both live.
- Stopwatch: start, lap at 1:30, lap at 3:00, stop and read times.
5. Limitations & known constraints
- Tab in background — Browsers may throttle timers in background tabs; stopwatch and countdown may be less accurate when the tab is not visible.
- No persistence — If you close the tab, stopwatch and countdown state are lost unless the tool saves to localStorage.
- DST — World clock uses IANA data; daylight saving is reflected automatically for supported zones.