Chronometer
A precise stopwatch with lap timing, running entirely in your browser tab.
00:00.00
Recommended Settings
Pro Tips
- •The timer keeps running accurately even if you switch tabs, since it's based on real elapsed wall-clock time rather than a fixed counter
- •Lap times show the total elapsed time at the moment each lap was recorded, not the duration since the previous lap
- •Pausing and resuming preserves your elapsed time exactly - only Reset clears it back to zero
- •For very long durations, the display automatically switches to include hours once you pass the one-hour mark
Most Popular
Most people use this as a simple browser-based stopwatch for workouts, cooking, or timing a task
When to Use This Tool
Track exercise duration or rest intervals with lap timing.
Time how long a task or activity takes from start to finish.
Capture individual lap times during a practice run or drill.
Keep track of elapsed time while rehearsing a talk.
How It Works
Record the real-world start time when you press Start, accounting for any previously accumulated elapsed time
Continuously recompute elapsed time as the current time minus the start time on each animation frame
Record a snapshot of the current elapsed time whenever you press Lap
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Client-side JavaScript timing (Date, requestAnimationFrame) for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
Will the timer stay accurate if I switch tabs?
Yes, since it calculates elapsed time from the actual start timestamp rather than counting ticks, so switching tabs or brief background throttling won't cause it to lose accuracy.
What do lap times show?
Each lap shows the total elapsed time at the moment you pressed Lap, not the time since the previous lap - so lap times will always be in increasing order.
Does the timer keep running if I close the tab?
No, the timer only runs while the page is open - closing or reloading the tab resets its state.
Is my timing data stored anywhere?
No. All timing happens locally in your browser and nothing is saved once you leave the page.