Online Stopwatch

How to use the online stopwatch

Click "Start" to begin timing — the display counts up in hours, minutes, seconds, and hundredths of a second, updating smoothly as it runs. Click "Lap" at any point to record a split without interrupting the clock; each lap is added to the table above, newest at the top, showing both the individual lap duration and the running total elapsed time at the moment you clicked. The "Lap" button stays disabled until the stopwatch is running, since a lap only makes sense once timing has begun.

Click "Stop" (the "Start" button relabels itself while running) to pause the clock. Clicking "Start" again resumes from exactly the time shown — it does not reset to zero — so you can pause between efforts and keep accumulating total elapsed time. "Reset" clears the display back to 0:00.00, wipes the lap table, and stops the clock entirely, ready for a fresh run.

Once you have recorded two or more laps, the fastest lap is highlighted in your chosen accent color and the slowest is tinted in a muted gray, so you can spot your best and worst splits at a glance without doing the math yourself. With only one lap recorded there is nothing to compare yet, so no highlighting is shown.

Elapsed time is measured with a monotonic high-resolution timer, so it stays accurate to the hundredth of a second even if your computer's clock changes or the tab is briefly backgrounded. Like every tool on this site, the stopwatch runs entirely in your browser with no installation and no internet connection required after the page loads.