Online Stopwatch
Millisecond-precision timing with unlimited lap capture.
What people time with this stopwatch
- Runs and workouts — lap splits around a track, rest periods, circuit times, or the length of a plank hold.
- Cooking and brewing — actual elapsed time of a reduction, a cold brew steep, or proofing dough when the recipe says “until it looks ready”.
- Work and study — honest time tracking of a task or a revision block; the lap button doubles as a task switcher.
- Experiments and demos — reaction-time tests, physics class measurements, or timing any process where a wall clock is too coarse.
- Games and practice — speedrun splits, chess clock drills, or how long your friend “really” takes to get ready.
How it works
The stopwatch measures 10-millisecond precision and records unlimited lap times — each lap shows its own split plus the running total. It runs entirely in your browser: no install, no account, no upload, and it works offline. Because it measures elapsed time rather than counting ticks, the reading stays true even if you switch to another tab mid-measurement.
Counting up is the right tool when you want to know how long something takes. When you need a reminder at a moment in the future, use the countdown timer or the online alarm clock instead.
Frequently asked questions
How accurate is it?
It displays hundredths of a second and uses your device's high-resolution clock, so it is accurate to a few milliseconds over minutes — more than enough for training, cooking and experiments.
Does it keep running in a background tab?
Yes. Elapsed-time measurement is immune to tab switching; your laps stay accurate even if the tab loses focus.
What is a lap time?
A lap records the stopwatch at the moment you press the button. We show both the split (time since your previous lap) and the cumulative total, which is the format runners and coaches expect.