Calculators & Time
A stopwatch with laps
Start, stop, and record laps. Each lap shows both its own duration and the total elapsed, which is the pair that actually tells you anything.
00:00.0
Timed against the system clock rather than by counting ticks, so it stays accurate even if the tab is in the background — where browsers throttle timers heavily.
- Runs in your browser
- No account required
- Free to use
How it works
Timed against the clock, not by counting
Elapsed time is the difference between now and when you started, read fresh on every update. A stopwatch that adds an interval to a counter drifts, and drifts badly in a background tab where the browser stops waking it.
Laps show both numbers
The lap duration and the total at that point. One without the other leaves you doing arithmetic to answer the obvious question.
What it does
Tenths of a second
Fine enough to be useful, coarse enough to read while it moves.
Pause and resume
Stopping keeps the elapsed time; starting again continues from it.
Accurate in a background tab
Browsers throttle timers in tabs you are not looking at — often to once a minute — so anything that counts its own ticks loses time. This compares against the system clock on every update, so switching tabs changes nothing about when it finishes.
Runs in your browser
No account and no upload — what you type is never sent anywhere. Analytics records that the tool was opened, never what you put into it.
Practical advice
Getting a better result
- Laps are listed newest first, so the one you just took is at the top.
- Reset clears the laps as well as the time — stop rather than reset if you want to keep them.
- Browser timing is accurate to a few milliseconds, which is well beyond the tenth of a second shown. It is not laboratory equipment, but it is not the limiting factor either.
Questions
Things people ask
How accurate is it?
To within a few milliseconds, because it reads the system clock rather than counting intervals. Your reaction time pressing the button is a far larger source of error than the stopwatch is.
Does it keep running in a background tab?
Yes. The display updates less often when the tab is hidden, but the elapsed time is calculated from the clock, so it is correct the moment you look at it again.
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