What it does
A stopwatch with Start, Stop, Lap and Reset, accurate to the millisecond. Press Start to begin timing, Lap at any point while it's running to record a split without stopping the clock, Stop to pause, and Reset to clear back to zero once stopped. Recorded laps are listed with their split time (time since the previous lap) and their running total, with the fastest and slowest laps highlighted once you've recorded more than one. Everything runs in your browser; nothing is sent anywhere, and timing continues correctly even if you switch tabs.
How it works
The stopwatch measures elapsed time using the browser's high-resolution timer, which is unaffected by the system clock being adjusted mid-session. While running, the display refreshes on every animation frame; while stopped, the elapsed time is held and Reset becomes available. A lap records the gap since the previous lap (or since Start, for the first lap) alongside the running total at that moment — that split figure is what gets compared to find the fastest and slowest lap once there are at least two.
Display format
Under an hour, the time shows as minutes:seconds.milliseconds, for example 01:05.432. Once the clock passes an hour, an hours segment appears, for example 1:01:01.050.
Common uses
- Workouts and training: timing intervals, runs or rounds, with laps for each repetition.
- Cooking and timing tasks: tracking how long something actually took.
- Presentations and speeches: keeping track of elapsed speaking time.
- Games and puzzles: timing an attempt at a puzzle or challenge.
- Comparing repeated attempts: using laps to see which run was fastest.
Frequently asked
Can I record a lap without stopping the clock?
Yes — Lap records a split and keeps timing running; only Stop pauses the clock.
What do the highlighted laps mean?
Once two or more laps are recorded, the fastest split is highlighted in green and the slowest in red, so you can spot your best and worst efforts at a glance.
Does switching tabs or minimising the browser affect accuracy?
No. The elapsed time is calculated from the browser's high-resolution clock rather than counted in fixed steps, so it stays accurate even if the display itself updates less often while the tab is in the background.
Can I reset while the stopwatch is still running?
No — Reset is only available once you've pressed Stop, so a running time is never cleared by mistake.
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