Stopwatch
Time races, experiments, presentations or workouts with a stopwatch that reads to the hundredth of a second. Record as many laps as you need, see which lap was fastest and slowest, and export every lap and split time as a CSV file for a spreadsheet.
Time Something
00:00.00
Stopped
Keyboard: Space or Enter on a focused button. Shortcut keys while the stopwatch area has focus: S start/stop, L lap.
Laps
Laps as CSV
How to Use the Stopwatch
- Press Start (it becomes Stop while running).
- Press Lap at each lap or checkpoint; the table shows lap time and total time.
- Press Stop to pause, Start to continue, and Reset to clear the time and laps.
- Copy or download the CSV of your laps.
About This Tool
Runners and coaches, science students timing experiments, speakers rehearsing, and anyone who needs split times.
Input: Start / stop / lap · Output: Times and CSV.
Features and Limitations
Features
- Hundredth-of-a-second display based on the high-resolution performance clock.
- Unlimited laps with fastest and slowest marked in words.
- CSV export of lap and split times.
- Keyboard shortcuts S and L inside the stopwatch, plus normal button operation.
Limitations
- Screen refresh limits what you see to about 60 updates per second; the recorded times are more precise.
- Laps are lost if you close or reload the page; export them first.
- Results are computed in your browser; nothing you enter is sent to a server.
Frequently Asked Questions
How accurate is it?
Times come from performance.now(), which is accurate to well under a millisecond. Human reaction time (about 0.2 seconds) is the bigger source of error.
What is the difference between lap and split time?
Lap time is the time since the previous lap press. Split (total) time is the time since you started.
Does it keep running if I switch tabs?
Yes. Time is measured from the clock, so it stays correct even if the display updates less often in the background.
Related Tools
More like this: all Timers & Clocks tools, all Productivity tools or the TinySandy home page.