Stopwatch

How to use the Online Stopwatch

1. Click the Start button or press Space on your keyboard to begin timing.
2. Press the Lap button or the L key to record a lap while the stopwatch is running.
3. Click Pause or press Space again to stop the timer. You can resume at any time.
4. Review your lap times in the table below. The fastest lap appears in green and the slowest in red.
5. Click Reset or press R to clear the stopwatch and start fresh.

Reading your splits

A lap time tells you how long that segment took; a split time (sometimes called cumulative time) tells you the running total since you hit start. Coaches usually want laps to spot which segment slowed a runner down; race officials usually want splits to match against a course map. This tool shows both side by side so you don't have to do the subtraction in your head mid-session.

Frequently asked questions

Does the timer keep running if I switch tabs or lock my phone?

On most modern browsers, yes. The timer uses your device clock rather than a visual redraw loop, so background tabs won't cause drift. Extremely aggressive battery-saver modes on some Android phones can still pause background JavaScript; if you're timing something for more than a few minutes unattended, keep the screen on.

How accurate is it?

It's bound by your browser's timer resolution, typically accurate to within a few milliseconds. Plenty for anything short of professional race timing, which uses dedicated hardware for good reason.

Can I rename laps?

Not yet. Each lap is numbered in order. If you need named segments (e.g., "warm-up," "sprint," "cool-down"), note the lap numbers as you go.