Stopwatch, Timer & World Clock
A stopwatch with laps, a countdown timer with alarm and notifications, and a live clock for any timezone — all in one place.
By Alex van den Berg · Last reviewed · How we test our tools
⏰ Time's up!
Choosing the right tool for the job
A stopwatch and a countdown timer solve opposite problems, and mixing them up is a common source of frustration. Use the stopwatch when you don't know in advance how long something will take and want to measure it — a workout, a presentation you're rehearsing, or how long a task actually takes versus your estimate. Use the timer when you know exactly how long you want something to last and need an alert when that time is up — cooking, focused work intervals, or limiting how long you spend on a break. The lap feature on the stopwatch is specifically for repeated segments of the same activity: each lap's "split" time is that segment alone, while "total" is the running time since you started, so you can spot whether you're speeding up or slowing down over a session.
The world clock solves a different problem again — coordinating across time zones rather than measuring duration. If you work with colleagues or clients in other countries, glancing at a static UTC offset is unreliable because more than 70 countries observe daylight saving time on different schedules, so a "UTC-5" label can silently become wrong twice a year. Using each city's actual IANA timezone identifier (like America/New_York rather than a fixed offset) keeps the displayed time correct automatically, which is the same approach used by calendar apps and scheduling software.
Frequently Asked Questions
How accurate is this stopwatch?
It measures elapsed time using your browser's high-resolution clock and updates the display every 50 milliseconds, which is accurate enough for virtually any everyday timing task. It is not certified for professional sports timing.
Will the timer still go off if I switch to another tab?
Yes. The countdown keeps running in the background using real timestamps, not just a tick counter, so it stays accurate even if the tab is inactive. If you allow notifications, you'll get a system notification plus a sound when it reaches zero, even if you're on a different tab.
Why does the timer need notification permission?
Browsers only allow a page to show a system notification (the kind that appears outside the browser window) if you've explicitly granted permission. Without it, the timer will still play a sound and flash on-screen when it finishes, but only while you're looking at the tab.
Does the world clock account for daylight saving time automatically?
Yes. Each city's time is calculated using its official IANA timezone (e.g. Europe/London, America/New_York), which automatically adjusts for daylight saving and other regional rules — the same data your operating system uses.
Why does the stopwatch show split and total lap times?
Total time is elapsed time since the stopwatch started, useful for overall pace. Split time is just that lap's duration on its own, useful for comparing individual segments — for example, seeing whether your third kilometre was faster or slower than your first, rather than only knowing the cumulative time at each point.
What's the difference between a countdown timer and a Pomodoro timer?
Technically nothing — a Pomodoro timer is simply a 25-minute countdown timer used as part of the Pomodoro Technique, a time-management method of alternating focused 25-minute work sessions with short breaks. The 25-minute preset above exists specifically for that use case, but the same countdown works for cooking, workouts, or any fixed-length task.
Is anything here sent to a server?
No. The stopwatch, timer, and clock all run entirely with JavaScript's built-in Date and timing APIs in your browser. Nothing is uploaded or logged anywhere.