About the Online Stopwatch
Tezmy's Online Stopwatch is a big, clear stopwatch that times to a hundredth of a second. Record lap or split times with one tap and it highlights your fastest and slowest laps automatically. On a computer, use the keyboard: Space to start and stop, L for a lap and R to reset. It keeps accurate time using your device's high-precision clock, so it's reliable for workouts, running intervals, cooking, presentations, experiments and games.
Updated October 2026
How to use the Online Stopwatch
- 1Press Start (or Space) to begin timing.
- 2Press Lap (or L) to record a lap time.
- 3Press Stop to pause and Resume to continue.
- 4Press Reset (or R) to start over.
Lap and split times
Press Lap each time you complete a lap or part of an activity. Each lap shows its own time (lap time) and the running total (split time). The fastest lap is highlighted in green and the slowest in red, so you can see at a glance how your pace changed.
Great for
- Running, swimming and cycling intervals.
- Timing presentations, speeches and practice talks.
- Science experiments and school races.
- Cooking, board games and speed challenges.
- Measuring how long tasks really take at work.
Keyboard shortcuts
On a computer, press Space to start and stop, L to record a lap and R to reset. It's much faster than clicking, especially when you're timing something that moves quickly.
Stopwatch vs timer
A stopwatch counts up from zero to measure time. To count down from a set time with an alarm, for cooking or Pomodoro study sessions, use the Countdown Timer.
Accurate timing
The stopwatch uses your device's high-precision clock rather than counting ticks, so it stays accurate even if the page is busy or you switch to another tab and back. Times are shown to a hundredth of a second, which is more than enough for sport and everyday timing.
Use it anywhere
Open this page in Safari, Chrome or Edge on your phone, tablet or computer. There's nothing to install and no sign-up, and everything runs on your own device, so what you type is never uploaded. To total laps into hours use the Hours Calculator, and to plan a call across cities use the Time Zone Converter.
Features
- Hundredth-of-a-second precision
- Unlimited laps
- Fastest and slowest lap highlighted
- Keyboard shortcuts
- Big, easy-to-read display
- Works offline once loaded
Frequently asked questions
How accurate is this stopwatch?
It uses your browser's high-resolution clock, which is accurate to well under a millisecond. The display updates every screen refresh.
What's the difference between lap time and total?
Lap time is how long that one lap took. Total is the time since you started, also called the split time.
Does it keep running if I switch tabs?
Yes. The time is calculated from when you pressed Start, so it stays correct even if your browser pauses the display in the background.
What are the keyboard shortcuts?
Space starts and stops, L records a lap, and R resets. They work as long as you're not typing in a box.
Can I count down instead?
Yes. Use our Countdown Timer, which also plays an alarm when time is up.
Does it work on my phone?
Yes. The big buttons are easy to tap. Keep the screen on for long sessions, as some phones pause pages when they lock.
How many laps can I record?
As many as you like. The list keeps every lap with its time and the running total.
Is it free?
Yes, free with no sign-up, and it works offline once the page is open.
Can I see my lap history after stopping?
Yes. Laps stay on screen until you press Reset, so you can review or write them down.
What does split time mean?
The total time from the start to the moment you pressed Lap. Lap time is the time since the previous lap.