⏱ Stopwatch Calculator
Measure elapsed time with start, stop, reset, and lap functionality. Useful for sports, productivity, and experiments.
Stopwatch
Batch Mode (CSV Upload)
Upload CSV lines like:
lap_time
00:02:15.123
00:05:30.456
The Stopwatch: From Mechanics to Digital
A stopwatch is a device designed to measure elapsed time precisely. Unlike a wall clock, it doesn’t show the current time — instead, it starts from zero and tracks forward. This makes it essential in sports, science, and productivity.
1. History
The first mechanical stopwatches emerged in the 18th century for horse racing. Later, analog models became standard in athletics. Today, digital stopwatches and smartphone apps dominate.
2. Key Features
- Start/Stop: Begin or pause the timer.
- Reset: Return to zero.
- Laps: Record intermediate times without stopping the main timer.
3. Applications
- Sports: Race timing, splits, performance analysis.
- Science: Lab experiments, chemical reactions, physics trials.
- Productivity: Pomodoro cycles, work session tracking.
4. Worked Example
Start stopwatch at race beginning. Lap 1 at 2:15.123, Lap 2 at 5:30.456, Final stop at 8:45.789 → output all laps plus total time.
5. FAQs
Does this stopwatch run in the background?
Only while the page is open — closing the tab will reset it.
Can I export lap times?
Yes, you can upload laps via CSV and also download results.
What’s the precision?
Milliseconds are displayed, though browser timing may vary slightly.
6. Conclusion
The stopwatch remains a timeless tool: simple in concept, but indispensable in practice.