How to use the stopwatch
- Press Start (or the Space bar) to begin timing.
- Press Lap (or L) to record a split without stopping – perfect for laps of a track or rounds of an exercise.
- Press Stop to pause. Press Start again to continue from the same time.
- Press Reset (or R) to clear the time and all laps.
The fastest lap is highlighted in green and the slowest in red, so you can quickly see where you gained or lost time. Use Copy laps to paste your splits into WhatsApp, a notebook or a spreadsheet.
Lap time vs total time
Each row in the table shows two numbers. Lap time is how long that single lap took – the time since the previous lap button press. Total is the time since you started. For example, if you press Lap at 1:05.20 and again at 2:08.90, the second lap time is 1:03.70 and the total is 2:08.90.
What can you time?
- Running and sports: 100 m sprints, 400 m laps, swimming lengths or cycling loops.
- Workouts: how long you can hold a plank, or how fast you finish a set of burpees.
- Speeches and presentations: practise until your talk fits the time limit.
- Science experiments: measure a pendulum's swing, a reaction or a falling object in school practicals.
- Everyday life: how long your commute, a cooking step or a puzzle really takes.
How accurate is an online stopwatch?
The stopwatch uses your device's high-precision clock, which measures time to a fraction of a millisecond, and shows hundredths of a second. The time itself stays correct even when the tab is in the background. In practice, the biggest source of error is human reaction time – usually around a quarter of a second when you press a button. For fair comparisons, have the same person press start and stop each time. Curious about your own reaction speed? Try our reaction time test.
Frequently asked questions
Does the stopwatch keep running if I switch tabs?
Yes. It measures time from the moment you pressed Start, so the time is correct whenever you come back to the tab.
How many laps can I record?
There is no practical limit. The table shows every lap, with the most recent one at the top.
What are the keyboard shortcuts?
Space starts and stops the stopwatch, L records a lap, and R resets it.
Is my data saved?
No. Times and laps stay only on this page and are cleared when you reset or close the tab. Use Copy laps to keep them.