Using an online stopwatch with laps
A stopwatch measures elapsed time: a run around the block, a presentation rehearsal, a recipe step, how long a build takes. A lap button turns it into a training tool by recording intermediate times without stopping the clock.
This stopwatch runs in your browser tab with millisecond display. Record laps to see both the split, the time since the previous lap, and the total time since the start.
How to use it
- Press Start to begin timing.
- Press Lap each time you pass a marker, finish a round or complete a step.
- Press Stop to pause; Start again continues from where you stopped.
- Read the lap table: Split is each lap on its own, Total is the running time. Press Reset to clear everything.
Example: how times are shown
83,456 ms 3,723,456 ms
01:23.456 1:02:03.456
Under an hour the display shows minutes, seconds and milliseconds. From one hour on, the hours appear in front.
Splits and totals
Runners and swimmers call the time of each segment a split. Comparing splits shows pacing: if the third of four laps is much slower, that is where effort dropped. The total column shows where you are against a target, such as a 5K goal time. Both are recorded at the same instant when you press Lap.
How accurate is it?
The stopwatch measures time from the browser's high-resolution clock rather than by counting ticks, so the elapsed time stays correct even if the display updates less often. Browsers slow down timers in background tabs to save battery; the display may pause while you look at another tab, but the measured time is still right when you come back.
The real limit is your reaction time when pressing the button, typically 0.15 to 0.3 seconds. For official sports timing, electronic start and finish systems are used for exactly that reason.
When to use a timer instead
A stopwatch counts up and tells you how long something took. To work in fixed blocks, for example 25 minutes of focus, use a countdown timer such as the Pomodoro timer, which alerts you when the time is up.
Questions
Does it keep running if I close the tab?
No. The stopwatch lives in the open page. Closing or reloading the tab ends the measurement.
Are my laps saved?
No. Laps exist only on the page until you reset or close it. Copy them out if you need to keep them.
Can I use it offline?
Yes. Once the page has loaded it needs no connection.