Online Stopwatch
Precise stopwatch with lap time tracking
Online Stopwatch
Precise stopwatch with lap timing
This free online stopwatch runs with millisecond precision: start with one tap, record unlimited laps and see your fastest and slowest laps automatically. Ideal for running and swimming sessions, HIIT sets, experiments and anything you need to time. Turn on periodic sound alerts at an interval you choose, follow the big digits in fullscreen, and toggle sound and vibration feedback. No sign-up, no app — everything runs in your browser.
Features
Millisecond Precision
Accurate to the millisecond
Lap Times
Record and view multiple lap times
Audio Alerts
Optional sound feedback
Fullscreen
Large display for easy viewing
Uses & Features
What people time
- Running, swimming and track laps
- HIIT and interval workouts
- Experiments, exams and work sessions
- Games and competitions
Features
- Millisecond precision
- Unlimited laps + fastest/slowest highlights
- Periodic sound alerts (minute/second intervals)
- Fullscreen, sound effects and vibration
Frequently Asked Questions
How accurate is this stopwatch?
The stopwatch is accurate to the millisecond using high-resolution browser timers.
Can I record lap times?
Yes! Press the lap button while the stopwatch is running to record split times.
Does it keep running if I switch tabs?
Yes, the stopwatch continues to run accurately even in background tabs.
Can I see my fastest and slowest lap?
Yes. The lap list automatically highlights your fastest and slowest laps, so differences stand out at a glance.
What are periodic alerts for?
They play a sound at an interval you choose (say, every minute) — great for pacing without watching the screen.
Is it free, and do I need an app?
It's completely free and runs directly in your browser on desktop, tablet and phone — nothing to install.