How to Use
- Start the stopwatch
Click the Start button to begin timing.
- Record laps or pause
Click Lap to record a split time, or Pause to temporarily stop the stopwatch.
- Reset
Click Reset to clear the stopwatch and start a new timing session.
What Is a Stopwatch?
A stopwatch is a timing tool that measures the elapsed time between a start moment and a stop moment. Unlike a clock that points to a specific time of day, a stopwatch treats any chosen instant as zero and accumulates the time that passes from that reference point.
Display and Uses
This stopwatch shows time in MM:SS.cc (minutes:seconds.centiseconds) format. A centisecond is one hundredth of a second, so you can read times down to 1/100 of a second. That makes it well suited to running intervals, cooking timings, measuring presentation length, and recording experiments or observations where short spans must be measured accurately. You can also record a lap without stopping, which lets you split and compare several segments within a single measurement.
Calculation Formula
The actual elapsed time is found from the difference between two high-resolution timer readings.
elapsed (ms) = performance.now() (now) - performance.now() (start)
Milliseconds are converted to MM:SS.cc as follows:
total centiseconds = floor(ms / 10)cc (centiseconds) = total centiseconds % 100SS (seconds) = floor(total centiseconds / 100) % 60MM (minutes) = floor(total centiseconds / 6000)
For example, 61,234 ms gives 6,123 total centiseconds → cc=23, seconds=1, minutes=1, so it is shown as 01:01.23. A lap time is calculated as current cumulative - previous lap's cumulative.