Online Stopwatch
A precise stopwatch right in your browser: laps, pause and full-screen mode. Made for training, kitchen timing, lab work and any elapsed-time measurement.
Laps
No laps yet. Hit “Lap” while the stopwatch is running to capture a split time.
How to use the stopwatch
Start the timer with one click, capture splits with laps and switch to full screen so the numbers are visible across the room.
Press “Start”
Time runs to the hundredth of a second. You can also use the Space bar.
Record laps
The “Lap” button stores a split. The fastest and slowest laps are tagged automatically.
Pause, reset, full screen
Pause to freeze the count. “Reset” clears time and laps. The button on the right expands the stopwatch to fill the screen.
Why this stopwatch
Hundredth-second precision
The stopwatch uses the browser’s monotonic clock (performance.now) and displays centiseconds without drift or jitter.
Smart lap list
Each lap shows its split time and the cumulative total. Fastest and slowest laps are highlighted — handy for interval training and pace comparison.
Works offline
Everything runs in the browser. State is persisted to local storage so an accidental reload won’t lose your time.
Stopwatch FAQ
What is a lap and when should I use it?
A lap captures a split time. When you hit “Lap”, the stopwatch records how long has passed since the previous lap and the total elapsed time. It’s the standard way to compare segments in running, swimming or weighted sets.
How do I make the stopwatch full screen?
Use the arrows button to the right of “Reset” — the stopwatch expands to fill the screen with huge numbers, readable from across the room. Exit with the same button or the Esc key.
How precise is this stopwatch?
Very. The count uses the browser’s monotonic clock (performance.now), which doesn’t drift like setInterval and isn’t affected by system clock changes. The display resolution is two digits after the dot — hundredths of a second.
Will my time survive a tab reload?
Yes. The stopwatch saves its state to local storage automatically. If you reload the page, the elapsed time and your laps are restored. “Reset” wipes everything, including the saved state.
Are there keyboard shortcuts?
Yes. Space starts and pauses, L records a lap, R resets. They’re handy on a laptop during a workout or experiment when you don’t want to look at the screen.
Is there a limit on the number of laps?
No. The lap list scrolls when it grows. Fastest and slowest laps get colored badges so you can spot them instantly.