Stopwatch
A free online stopwatch that times to the hundredth of a second, records lap and split times, and downloads your laps as a CSV file.
- Free
- No sign-up
- Laps and splits
- CSV download
Stopwatch
Reset and clear all laps?
Keyboard: Space to start or stop, L for a lap, R to reset, F for full screen. Turn shortcuts off with the Keyboard shortcuts box above.
You have reached 999 laps. Download the CSV, then press Reset to start again.
Laps
| Lap | Lap time | Split | Note | Remove |
|---|
Press Ctrl+C or Cmd+C to copy.
Lap time vs split time
Lap time is how long one lap took, from the previous press of Lap to this one. Split time is the running total on the stopwatch at that moment.
Say four laps take 1:53.76, 1:49.80, 1:55.11, and 1:52.40. Each split adds that lap to the running total:
| Lap | Lap time | Split time |
|---|---|---|
| 1 | 1:53.76 | 1:53.76 |
| 2 (fastest) | 1:49.80 | 3:43.56 |
| 3 (slowest) | 1:55.11 | 5:38.67 |
| 4 | 1:52.40 | 7:31.07 |
The stopwatch labels the fastest and slowest laps for you once you have three laps or more.
Training in set work and rest periods rather than laps? A workout interval timer beeps at each change so you don't have to watch the clock.
How to use the stopwatch
- Press Start or the space bar.
- Press Lap or L at the end of each lap. Type in the note box under or beside any lap if you want to remember what it was. Notes are saved with your laps and go into the CSV.
- Press Stop when you're done. Press Start again to carry on from the same time.
- Copy the table or download it as a CSV file, then press Reset to clear it.
More timers and time tools
- Online timerCount down from any time, with an alarm.
- Add up durationsTotal several timed runs or laps with the timer calculator.
- Elapsed time calculatorThe time between two clock times.
- Interval timerRun timed work and rest rounds instead of counting up.
- 1 minute timerCount down one-minute rounds instead of counting up.
- Focus timerWork in timed focus sessions with short and long breaks.
- Online alarm clockSet up to three alarms for a time of day, with snooze.
Stopwatch questions
What is the difference between lap time and split time?
Lap time is how long one lap took, measured from the previous lap. Split time is the total time on the stopwatch when you pressed Lap. If your laps take 1:53.76 and then 1:49.80, the second lap's split is 3:43.56.
Will I lose my times if I refresh or close the tab?
No. The current run and its laps are saved in your own browser every time something changes, so a refresh or an accidental close picks up where you left off. Reset clears it. Nothing is sent to a server.
How accurate is an online stopwatch?
The stopwatch reads your device clock, so it doesn't drift over a long run. The limit is reaction time: the delay between seeing something and pressing a key is usually much larger than a hundredth of a second. It's fine for training and everyday timing, but not for official race or competition timing.
Can I export my laps to Excel or Google Sheets?
Yes. Download CSV saves a file that opens in Excel, Google Sheets, or Numbers, with a row for each lap, a total row, and an average row once you have two or more laps. Copy puts the same table on your clipboard, ready to paste into a spreadsheet.
Does it keep running if my phone screen locks?
The time stays correct, because the stopwatch works out the elapsed time from the moment you started. The display just catches up when you unlock. Turn on Keep screen awake if you want to watch it the whole time.
Sources
- Chrome for Developers, "Heavy throttling of chained JS timers beginning in Chrome 88" (background tabs slow down timers), developer.chrome.com
- web.dev, "The Screen Wake Lock API is now supported in all browsers" (Keep screen awake), web.dev
The stopwatch on TimerCalculator.com was built by Cedrick Reese. It works out elapsed time from the moment you pressed Start rather than counting ticks, so the time stays right through a locked screen or a background tab. It was tested in an automated browser with a simulated clock: four laps timed like the worked example above were recorded and their lap times, splits and Fastest and Slowest labels were checked, one lap was removed to confirm its time folded into the next lap and the splits still reached the same total, the page was reloaded mid-run to confirm the laps came back, and a note typed on a 390 pixel wide phone screen was checked in the downloaded CSV. Your laps are saved only in your own browser.