Stopwatch

A simple online stopwatch that starts, laps, and resets right in your browser — accurate to the hundredth of a second, no app required.

A stopwatch seems like the simplest tool imaginable, but the details matter more than they get credit for. The whole point of a stopwatch is that it never gets in your own way — you press one button and it starts counting, you press another and it records a split without losing the running total, and you can trust the number on the screen down to the hundredth of a second. That reliability is why stopwatches outlasted almost every other piece of "obvious" technology: coaches still use them courtside, teachers use them for timed tests, and cooks use them for anything more precise than a kitchen timer's minute-level granularity.

What makes a browser-based stopwatch worth using over the one built into your phone is mostly about friction. There's no app to open, no permission prompt, no ad interstitial before the numbers start moving — you land on the page and it's already there, timing whatever you need timed. The lap function is the part people underestimate: being able to mark a split without stopping the clock is what separates "a stopwatch" from "a timer that also shows elapsed time," and it's the feature that makes this useful for interval training, multi-stage cooking, or timing several runners in a race without resetting between each one.

Because everything runs locally in JavaScript rather than on a server somewhere, there's also no lag between pressing the button and the clock actually starting — the interaction is as close to instant as a browser allows, which matters more than it sounds like it should when you're trying to time something to the hundredth of a second.

1. Press Start to begin timing.
2. Press Lap at any point to record a split without stopping the clock.
3. Press Pause to stop the clock, or Resume to keep going.
4. Press Reset to clear the display and lap list.