How to use the stopwatch
Press Start (or the space bar) to begin timing and Stop to pause. Press Start again to continue from where you stopped. Reset sets the stopwatch back to zero and clears all laps.
While the stopwatch is running, press Lap to record a lap. Each row shows the lap time (marked with +) and the total time, with the newest lap at the top. Press Full screen to show the time large.
What you can time
- Running and swimming — Record every lap on the track or in the pool and compare your pace.
- Workouts — Time planks, rest between sets or a whole training session.
- Speeches and presentations — Practice until your talk fits the time limit.
- Science class — Measure how long an experiment takes, like a pendulum swing or a ball rolling down a ramp.
- Puzzles and games — Time your Rubik’s Cube solves or each round of a quiz.
- Cooking — See how long something has been on the stove when you don’t know the time in advance.
FAQ
How accurate is the stopwatch?
It shows hundredths of a second and measures time with your device’s clock, so it stays accurate even over long periods. Keep in mind that pressing the button by hand adds a small reaction delay, usually around 0.2 seconds.
Does it keep running if I switch tabs?
Yes. The elapsed time is calculated from the clock rather than counted step by step, so it is still correct when you come back. Don’t close or reload the page, or the stopwatch will start over.
What is the difference between lap time and total time?
Lap time is how long one lap took — the time since you last pressed Lap. Total time is the time since you started. For example, if you press Lap at 1:10 and again at 2:25, the second lap time is 1:15 and the total time is 2:25.