Online stopwatch
Hundredths of a secondLapsFull screen
Space to start or stop, L for a lap, R to reset, F for full screen.
| Lap | Lap time | Total |
|---|
Press Start or the space bar and the stopwatch counts up in hundredths of a second. Press Lap, or L, to split off a lap without stopping the clock. The watch works from the time you started it rather than counting ticks, so it stays right in a background tab, and a reload keeps both the time and the laps.
How laps work
Each row in the lap list has two times: the lap itself, measured from the previous press, and the total since you pressed Start. Say you time three laps of a track and press Lap at 1:32.10, 3:05.40 and 4:41.00. The laps are 1:32.10, 1:33.30 and 1:35.60, and the totals are the times you pressed. Once you have two laps that differ, the fastest shows in green and the slowest in red, and the lap in progress counts up under the main time.
Keyboard shortcuts
- Space starts, stops and resumes.
- L records a lap while the watch runs.
- R resets it, once it’s stopped.
- F goes full screen. Press F or Esc to come back.
Full screen makes the digits big enough to read across a gym or a classroom. While it runs, the stopwatch asks your device to keep the screen on, where the browser allows it, so a phone propped on a bench doesn’t go dark halfway through a set.
Questions people ask
How accurate is an online stopwatch?
The stopwatch reads your device’s clock, which is good to a few thousandths of a second, so the time it shows is right. The weak point is the person pressing the button. Reaction time to a sound or a light is about a fifth of a second, so hand timing is fine for practice, a run or a game, but not for an official race result.
Does the stopwatch keep running if I switch tabs or lock my phone?
Yes. It keeps the moment you pressed Start and works the time out from that, so a background tab, a locked phone or a laptop that went to sleep doesn’t throw it off. When you come back it shows the right time. The tab title shows the time while it runs.
Will I lose my laps if I reload the page?
No. The time and the laps are kept for as long as the tab is open, so a reload picks up where you left off, still running if it was. Closing the tab clears them, so copy the laps first if you need them.
How do I reset the stopwatch?
Stop it first with the Stop button or the space bar, then press Reset or R. Reset is switched off while the watch runs, so a stray key press can’t wipe a time in progress.
How do I save or copy my lap times?
Press Copy laps under the lap list. Each lap goes on its own line with the lap time and the running total, and the fastest and slowest are marked, so you can paste the list into a note, a message or a spreadsheet.
Other timers
To count down from a set time, use the countdown timer. For workouts with work and rest rounds, the interval timer beeps at every change, and the alarm clock rings at a time of day while the tab is open. Counting the days to a race or a trip instead? The Countdown app for iPhone does that.