Stopwatch
Stopwatch with split lap timer.
{{ formatMs(watch) }}
| Split | Time | Length |
|---|---|---|
| {{ laps.length - i }} | {{ formatMs(lap.time) }} | {{ formatMs(lap.diff) }} |
Tips
- Lap time records the elapsed time for each segment; split time records the cumulative time from the start.
- It can also be used for tracking work sessions or the Pomodoro Technique (25 minutes of focus → 5 minutes of rest).
- Closing the browser tab will reset the stopwatch. Avoid closing the tab during long measurement sessions.
- You can save the lap time list by taking a screenshot of the screen.
FAQ
Side Note — World Speed Records — Various Speeds Measured with a Stopwatch
What speed do humans perceive as "fast"? Usain Bolt's world record in the 100m sprint, set at the 2009 Berlin World Championships, was 9.58 seconds. His top speed reached 44.72 km/h (about 12.4 m/s).
By comparison, the Tokaido/Sanyo Shinkansen "Nozomi" has a top speed of 285 km/h (about 79.2 m/s) — roughly 6 times faster than Bolt. F1 cars top out at over 370 km/h, the speed of sound (in dry air at 0°C) is about 1,224 km/h, and the speed of light is approximately 1.08 billion km/h (circling the Earth about 7.5 times per second).
In the world of milliseconds, a stopwatch can time the fastest F1 pit stop (Red Bull 2023: 1.80 seconds) and the average human blink (0.15–0.4 seconds). The average human reaction time is about 0.2–0.25 seconds — which is also roughly the "dead time" between a traffic light turning green and pressing the accelerator.
Incidentally, a hummingbird flaps its wings about 50–80 times per second — just 12–20 milliseconds per beat. The natural world is full of remarkable speeds.