A stopwatch answers the opposite question to a timer: not how long is left, but how long something took. Press start and the display climbs from zero through minutes, seconds and hundredths, ready to be stopped, read and reset without any setting-up first.
Saturday mornings give it an obvious job. parkrun starts at nine o'clock across England, Wales and Northern Ireland, and half past nine in Scotland, and the barcode scanner at the finish will give you an official time eventually — but plenty of people want their own reading on the spot, or want to time a friend who is pacing them. The same goes for a club night at the track, a swim set, or simply finding out whether the walk to the station really does take twelve minutes.
What it does
- Start, stop and reset from a single control
- Lap splits recorded without interrupting the running total
- Hundredths of a second on the display for short efforts
- Long runs held without needing to be restarted
On accuracy, the honest position is this: a browser measures time with the clock the operating system gives it, and background tabs can be throttled to save battery, so a stopwatch left running behind a dozen other tabs may update its display less smoothly than one you can see. Over a five-minute effort the difference is far smaller than your reaction time on the stop button. For anything official — a race result, a laboratory measurement, a record attempt — dedicated timing equipment exists for good reason and this is not a substitute for it.
Nothing is stored anywhere but your own device, and nothing is sent off to be recorded. Close the tab and the reading goes with it, so write down anything you want to keep before you navigate away. There is no history, no leaderboard and no export, which suits the way most people use a stopwatch: once, for one thing, and then never think about it again.
Common questions
How accurate is a stopwatch that runs in a browser?
Accurate enough for training, cooking and everyday timing, where the delay in your own thumb hitting the button matters more than anything in the software. It is not suitable for official race results or laboratory measurement.
Can I take lap times?
Yes. Recording a lap saves the split and leaves the main clock running, so you can collect several intervals within one continuous session.
Are my times saved anywhere?
No. Everything stays in the page on your own device, and closing the tab clears it. Note down anything you want to keep before you navigate away.
Will it still count if I switch tabs mid-run?
The count carries on, though the visible display may update less frequently until you return, because browsers deliberately throttle pages you are not looking at.
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