Online Stopwatch
العربيةStart timing with one tap and record laps while running, training or studying. The stopwatch shows hundredths of a second and highlights your fastest and slowest laps automatically.
Updated October 27, 2026Runs in your browser — nothing you enter is stored
00:00.00
Shortcuts: Space to start/stop, L for lap, R to reset.
How to use the stopwatch
- 1Press Start or the space bar to begin.
- 2Press Lap or the L key to record a split without stopping.
- 3Press Stop to pause and Resume to carry on from where you left off.
- 4Press Reset or the R key to start again.
Lap time vs total time
Lap time is the time since the previous lap — handy for comparing rounds, such as each 400 m on a track. Total time is everything elapsed since you started, up to the moment you recorded the lap.
Once you have two or more laps, the fastest is shown in green and the slowest in red, so you can spot where your pace dropped.
How accurate is it?
The stopwatch uses the browser’s high-resolution timer (performance.now), which is not affected if the device clock changes, and refreshes the display every frame. That makes it well suited to workouts, study sessions and simple experiments.
Remember that human reaction time typically adds around a tenth of a second when you press a button, so no manual stopwatch replaces electronic timing in official competitions.
To turn time and distance into speed, try the pace calculator; to count down instead, use the countdown timer.
Examples of stopwatch use
- Running and walking: record a lap every kilometre to see your pace for each part of the distance.
- Swimming: compare each length to track progress between sessions.
- Studying: measure how long a set of problems really takes.
- Cooking and experiments: time a reaction or cooking step precisely.
- Speeches and presentations: rehearse to stay within your time slot.
Example: 5 kilometres in 27 minutes 30 seconds is an average of 5 minutes 30 seconds per kilometre, or about 10.9 km/h.
Frequently asked questions
Does it keep running in another tab?
Yes. Time is measured from when you pressed Start, so it is still correct when you come back.
How many laps can I record?
There is no practical limit; laps appear in a table with the newest first.
What are the keyboard shortcuts?
Space to start or stop, L for a lap and R to reset.
Are my times saved?
No. They are cleared when you close or refresh the page, so copy them if you need them.
How precise is it?
It displays hundredths of a second; real-world precision depends on how quickly you press the button.
What is the difference between a stopwatch and a countdown timer?
A stopwatch counts up to measure elapsed time; a countdown timer counts down from a set duration to zero and then alerts you.