Introducing the Online Stopwatch — Millisecond Lap Timer

The new Stopwatch gives you millisecond-precision timing with unlimited lap splits, right in your browser. No install, no sign-up.

What it does

• Millisecond display — MM:SS.mmm, switching to H:MM:SS.mmm past the hour mark
• Unlimited laps — each press records a split; the table shows lap time and running total
• Fastest / slowest highlighting — green for best lap, red for worst; summary bar shows average
• Keyboard shortcuts — Space to start/pause, L to lap, R to reset
• Copy all laps — TSV export for Excel or Google Sheets

Accurate even in background tabs

Unlike setInterval-based timers, the stopwatch uses performance.now() — the browser’s monotonic high-resolution clock. Elapsed time is computed as current − start + accumulated, so pausing, resuming, and switching tabs introduce zero drift.

Try it

Open Stopwatch and start your next workout interval, cooking timer, or reaction time test. To learn about lap splits and keyboard shortcuts in detail, read the Stopwatch Guide.