⏱️ Stopwatch
A precise stopwatch with millisecond accuracy. Start, pause, reset, and record lap times — all in your browser.
About the Stopwatch
This stopwatch runs entirely in your browser and measures elapsed time with millisecond precision. It uses the high-resolution performance.now() clock, so timing stays accurate even if the browser throttles background tabs. You can start and pause as many times as you like, record lap times to compare splits, and reset everything to zero.
What is a lap time?
A lap time is the duration between two consecutive lap presses — in other words, how long the most recent segment took. The total elapsed time keeps running while you record laps, so you can see both the split for each segment and the overall time. This is useful for timing repetitions, runs, or any activity broken into intervals.
How to use this stopwatch
- Press Start to begin timing. The display updates every few milliseconds.
- Press Lap at any point to record the current split without stopping the clock.
- Press Start again (it toggles to Pause) to halt the timer.
- Press Reset to clear the time and all laps.
Frequently asked questions
Is the timing accurate to the millisecond? Yes. The stopwatch reads from performance.now(), which provides sub-millisecond resolution in modern browsers. Display rounding is to the nearest millisecond.
Does it keep running when I switch tabs? The clock keeps counting based on wall-clock time, so the elapsed value stays correct when you return. However, the on-screen digits only update while the tab is visible.
Does this tool upload any data? No. Everything happens locally in your browser.