Free tool
Online stopwatch
Start, stop and record laps, accurate to the hundredth of a second. It keeps running in a background tab — or even if you close the page — and the fastest and slowest laps are marked for you.
Stopwatch
00:00.00
Space start/stop · L lap · R reset · survives closing the tab
How to use the stopwatch
Press Start (or Space). While it runs, Lap records the time for that lap and the running total; newest laps appear at the top. Press Stop to pause — you can resume from the same point — and Reset to clear everything once it's stopped.
Good for
- Running and swimming laps, intervals and circuits.
- Timing a talk, a presentation rehearsal or a reading.
- Tracking how long a task really takes, versus how long it feels.
- Classroom activities and games.
Need to count down instead?
A stopwatch counts up from zero. If you need something to ring after a set time, use the online timer; to ring at a clock time, the online alarm clock. For naps, the pages like wake me up in 20 minutes set the alarm for you and explain what each nap length does.
And if the thing you're really trying to time is how long you lie in bed after the alarm — WakeUpBroo is an iPhone alarm that makes that number zero. No snooze, no dismiss button: it stops only when you type a code from wakeupbroo.com/code on a device across the room.
FAQ
Frequently asked questions
Is this stopwatch accurate?
Yes. It measures elapsed time against your device's clock rather than counting ticks, so it doesn't drift — even when the tab is in the background and the display updates less often. It shows hundredths of a second, which is finer than human reaction time when you press the button.
Does it keep running if I switch tabs or close the page?
Yes to both. Elapsed time is calculated from when you pressed Start, so switching tabs or apps doesn't lose any time, and the running time shows in the tab title. If you close the tab or the browser, the stopwatch and its laps are saved on this device — reopen the page and it's still running from the same start.
What's the difference between a lap and a split?
Here, the split is the time for that lap alone, and the total is the time since you started. Once you have three or more laps, the fastest and slowest splits are marked so you can compare them at a glance. Copy laps puts them on your clipboard in a format that pastes straight into a spreadsheet.
Are there keyboard shortcuts?
Space starts and stops, L records a lap, and R resets.
Is it free?
Yes — no signup, no download, no ads. It's a free tool from the makers of the WakeUpBroo iPhone alarm app.
Recommended next
Keep reading
Timing your mornings? Start with getting up.
WakeUpBroo is an iPhone alarm with no snooze and no dismiss button — it stops only when you read a rotating code from this website on another device, so you're out of bed before it's quiet. Free to download, 7-day free trial.
Free to download on iPhone · Android in development