Stopwatch

Does the stopwatch keep running in the background?

Yes, it saves the start timestamp and calculates elapsed time when you return. The displayed time will be accurate even after closing and reopening the tab.

What are lap times?

Pressing Lap records a split. The lap time column shows the duration since the previous lap, while the total column shows cumulative elapsed time.

How accurate is this stopwatch?

It is accurate to about 10 to 16 milliseconds, limited by browser timing precision. This is sufficient for most practical timing needs.