Online Stopwatch & Timer — Lap Times and Full-Screen Mode
00:00.00
| Lap | Split | Total |
|---|
05:00
A combined stopwatch and countdown timer that runs entirely in your browser. Time anything to the hundredth of a second, record unlimited laps with fastest/slowest highlighting, or set a countdown with quick presets and a sound alert. Hit full-screen mode to read the clock across a room.
How it works
- 1 Pick stopwatch or timer Use the tabs to switch between the count-up stopwatch and the countdown timer. Both keep their own state, so you can flip between them without losing your place.
- 2 Start, pause, and record laps Press Start to run the clock. On the stopwatch, tap Lap to mark a split — the fastest lap turns green and the slowest turns red. Pause and resume any time.
- 3 Set a countdown or go full-screen For the timer, type hours, minutes, and seconds or tap a preset like 5 or 25 minutes. Press the full-screen button to fill the display when you need to see it from a distance.
Your data stays private
All processing happens entirely in your browser. No files, text, or data are ever sent to our servers. You can disconnect from the internet and this tool will still work.
Frequently asked questions
- Does the stopwatch keep running if I switch tabs?
- Yes. The timing is based on the system clock, not on screen redraws, so the elapsed time stays accurate even if the browser tab is in the background or the screen sleeps. The display catches up when you return.
- How precise is the stopwatch?
- It shows hundredths of a second (centiseconds). The underlying measurement uses the system clock, so it is accurate to the millisecond — the two-decimal display is just for readability.
- Will the timer make a sound when it finishes?
- Yes. When the countdown reaches zero it plays a short three-beep alert using the browser's Web Audio API and the display flashes red. Make sure your device is not muted.
- Can I record more than one lap?
- Yes, laps are unlimited. Each lap shows its own split time and the cumulative total. The fastest and slowest laps are highlighted automatically once you have at least two.
- What does full-screen mode do?
- It expands just the clock to fill your whole screen with a large, easy-to-read display — useful for workouts, presentations, classrooms, or timing across a room. Press Escape or the button again to exit.
- Is my data sent anywhere?
- No. The stopwatch and timer run completely in your browser with JavaScript. Nothing is uploaded, logged, or stored on a server — you can even use it offline once the page has loaded.