Online Stopwatch
Press Start (or Space) to begin. Record laps with L, see your fastest, slowest and average lap, label each lap, and export the results as CSV — all in your browser, nothing sent to a server.
Laps
- Laps
- 0
- Fastest
- —
- Slowest
- —
- Average
- —
| # | Label | Lap | vs. avg | Total |
|---|
Click a label to rename the lap. Laps are kept if you reload the page.
Keyboard shortcuts
| Space | Start / pause |
|---|---|
| L or Enter | Record a lap |
| R | Reset (asks first if you have laps) |
| F | Fullscreen |
How accurate is it?
Elapsed time is measured with performance.now(), a monotonic clock with sub-millisecond resolution that does not jump when your computer's clock is adjusted or synced. The display redraws at your screen's refresh rate (about every 16 ms at 60 Hz), so the last digit is a readout, not a promise — the recorded lap and total times are exact to the millisecond of your key press or tap.
The stopwatch keeps counting in a background tab and across a reload: its start time is saved to your browser's local storage, and when the page comes back it credits the wall-clock time that passed. While it runs, the elapsed time is shown in the tab title and the screen is kept awake on supporting browsers.
Timing a fixed duration instead? Use the countdown timer or the Tabata interval timer.