Free Online Stopwatch
Stopwatch with lap times and countdown timer — accurate to the centisecond. Use Space to start/stop, R to reset, L to record a lap.
How to Use the Online Stopwatch
Two modes, zero learning curve.
Stopwatch Mode
Click Start (or press Space) to begin timing. Press L to record a lap without stopping — each lap shows the split time. Press R to reset.
Countdown Timer
Switch to Countdown, set your hours, minutes and seconds, then press Start. The timer counts down to zero and alerts you when time's up.
Keyboard Shortcuts
Space starts and pauses. R resets. L records a lap (stopwatch mode only). All shortcuts work without clicking — useful during workouts or presentations.
Frequently Asked Questions
How accurate is this online stopwatch?
The stopwatch uses the browser's high-resolution Performance API (requestAnimationFrame + performance.now()) and is accurate to the centisecond — that's 1/100th of a second. For everyday use such as cooking, workouts, meetings and presentations, this is more than sufficient.
Does the stopwatch keep running if I switch tabs?
Yes. The elapsed time is calculated using timestamps rather than tick counts, so switching tabs or minimising the browser does not affect accuracy. The display will update when you return to the tab.
How do I record lap times?
While the stopwatch is running, press the Lap button (or press L on your keyboard). Each lap records the total elapsed time at that moment and shows the split time — how long that individual lap took — in the list below.
Can I set a countdown timer for any duration?
Yes. Switch to Countdown mode, enter any combination of hours, minutes and seconds up to 23:59:59, and press Start. The timer counts down in real time and displays a completion message when it reaches zero.
What are the keyboard shortcuts?
Space starts and pauses the timer. R resets it to zero. L records a lap when in stopwatch mode. These shortcuts work without clicking, making the stopwatch practical for hands-free use during workouts, experiments or classroom activities.
What is the best online stopwatch?
ToolStack's Online Stopwatch offers millisecond accuracy, lap recording with split times, a built-in countdown timer, and full keyboard control — all in a clean, ad-light interface. No download, no signup, works on any device.
Does this work on mobile?
Yes. The stopwatch is fully responsive and works on any smartphone or tablet browser. The large tap targets make Start, Lap and Reset easy to press without zooming in.
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