How the online stopwatch works
- Click Start or press the space bar. Time is shown in hundredths of a second.
- Press Lap to record split times without stopping the clock.
- Stop pauses the stopwatch, Resume continues from the same point.
- Reset sets everything back to zero.
Record and compare lap times
Every lap shows its own time and the running total. From three laps on, the fastest lap is marked green and the slowest red. “Copy times” puts all laps on your clipboard as a table, ready to paste into Excel, Google Sheets or a message.
Accurate, even in the background
The stopwatch measures time with your device’s system clock, so it stays exact when you switch tabs or the browser throttles the page. Its state is saved locally: reload the page or open it again later and the time continues at the right point. While it runs, your screen stays on.
What you can use it for
- Sport: laps on the track, swimming lengths, intervals and personal bests.
- Studying: track how much time you really spend learning.
- Classrooms: time experiments, races and reading, big and clear in fullscreen.
- Speeches and presentations: find out how long your talk actually takes.
- Games: puzzles, Rubik’s cube solves and quiz rounds.
Stopwatch or timer?
A stopwatch counts up and measures how long something takes. A timer counts down from a set time and sounds an alarm at the end. For countdowns use our online timer or a fixed duration such as the 5 minute timer.
Frequently asked questions
How accurate is the online stopwatch?
It displays hundredths of a second and measures with your device’s system clock. In practice the biggest error is your own reaction time when clicking, which is around two tenths of a second.
Does the stopwatch keep running if I close the page?
Yes. The start time and laps are stored locally in your browser. When you open the page again, it shows the time that has passed since you started.
Can I save my lap times?
“Copy times” copies all laps to your clipboard as a table. They also stay in your browser until you press reset.
Are there keyboard shortcuts?
Yes: space starts and stops, L records a lap, R resets and F toggles fullscreen.