About this stopwatch
This free online stopwatch measures elapsed time accurately to the centisecond (1/100th of a second). It runs entirely in your browser using JavaScript's Date.now() for timing — no plugins, no downloads, no account required. It works on desktop and mobile, and continues running accurately even if you switch tabs (it records wall-clock time, not animation frames).
How to use it
Press Start to begin counting. Press Stop (the same button) to pause the time. Press Lap while running to record the current elapsed time as a lap — laps appear in reverse order so the most recent is always at the top. Press Reset to clear everything back to zero. The display shows minutes, seconds, and centiseconds (or hours if the time exceeds 60 minutes).
When to use an online stopwatch
An online stopwatch is useful any time you need to measure elapsed time without a physical device. Common uses include timing cooking, workouts, study sessions (Pomodoro technique), speeches or presentations, game turns, science experiments, and speed tests. The lap feature is especially handy for interval training — record each lap without stopping the overall timer.
Accuracy
The display updates every 10 milliseconds and shows centiseconds (hundredths of a second). The actual timing uses wall-clock time via Date.now(), which means the timer stays accurate even when the browser throttles JavaScript timers in background tabs. For ultra-precise timing (sub-millisecond), dedicated hardware or OS-level tools are more appropriate — but for everyday use this stopwatch is more than accurate enough.