Stopwatch
Online stopwatch with lap times, accurate to 10 ms.
🔒 100% browser-based — your data never leaves your device.
About this tool
A clean stopwatch that measures elapsed time to hundredths of a second, with a lap button that records split times as you go. Timing is based on the system clock rather than counting ticks, so it stays accurate even when the browser throttles background tabs.
Handy for sports training, cooking, speedcubing, work sessions or timing anything at all — on any device with a browser.
Frequently asked questions
How accurate is it?
Display updates every 30 ms, but elapsed time is computed from the system clock, so accuracy is within a few milliseconds regardless of display rate.
What is the difference between lap and split?
This stopwatch records both: each lap row shows the lap time (since the previous lap) and the total time (since start).
Does it keep running in a background tab?
Yes. Because time is derived from the clock, the reading is correct when you come back, even if the display paused while hidden.