Online stopwatch
00:00.00
Shortcuts: Space = start/stop · L = lap · R = reset
Laps
What is this stopwatch?
The AlarmClock24 online stopwatch measures elapsed time with millisecond precision. Press start, stop, and record laps whenever you want. Each lap is timestamped, and the full list can be copied to the clipboard for your records.
The stopwatch is built on performance.now(), a monotonic clock that never
jumps when the system time changes — unlike stopwatches based on wall-clock time.
That makes it dependable for sports timing, presentations, study sprints, and lab-style measurements.
Keyboard shortcuts
- Space — start / stop.
- L — record a lap.
- R — reset.
Shortcuts work while the page is focused, so you can time a race or a speech without touching the mouse.
Typical uses
- Sports: laps on a track, rest times between sets.
- Speaking: keep a talk or presentation inside its time limit.
- Study: time how long a task actually takes to plan better.
- Work: track billable blocks for freelancers.
Frequently asked questions
How accurate is the stopwatch?
It uses the browser's monotonic performance clock with millisecond precision, so it never drifts when the system clock is adjusted.
Can I export my laps?
Yes, the "Copy laps" button copies the full lap list to your clipboard as text, ready to paste anywhere.
Does it work with keyboard only?
Yes — Space starts/stops, L records a lap, R resets. Everything is also reachable with the on-screen buttons.