How to use Stopwatch
- Press Start, or the Space bar on a keyboard, to start the stopwatch.
- Press Lap (or L) at the end of each lap. Each lap shows its own split time and the running total.
- Press Stop to pause and Resume to carry on from the same time; press Reset (or R) to go back to zero.
- Copy the laps or download them as a CSV file to open in Excel or Google Sheets.
Why use Stopwatch
Laps and splits
Every lap shows its split and the total, newest first. With three laps or more, the fastest and slowest are marked.
Exact timing
Time is measured from the moment you press Start, so a slow or busy page never loses time.
Keyboard shortcuts
Space starts and stops, L records a lap and R resets, so you can time without looking for buttons.
Full screen
Show large digits to a class, a gym or a lab while you keep your hands free, a stop watch the whole room can read.
About this tool
A stopwatch measures how long something takes: a run or a swim, laps of a track, a speech, an experiment in a science class, or the time a batch of work really needs. This online stopwatch shows minutes, seconds and hundredths, and adds hours after the first hour. A lap timer records the split for each lap, which is how coaches compare laps and runners check their pace.
The stopwatch reads the time from your device’s clock when you press Start and again as it runs, instead of counting ticks, so it does not fall behind when the page is in a background tab or the phone is busy. Human reaction time, about a fifth of a second, is a bigger source of error than the stopwatch itself, so for the fairest results the same person should press the buttons each time.
Frequently asked questions
How accurate is this stopwatch?
It shows hundredths of a second and measures time with your device’s own clock, so it does not drift. Your reaction when pressing the button, about 0.2 seconds, matters more.
Does it keep running in another tab?
Yes. It keeps exact time while you use other tabs or apps. Closing or reloading the page resets it.
How many laps can I record?
As many as you need. The list scrolls, and Copy or CSV gives you every lap with its split and total.
What are split times?
A split is the time of one lap on its own. The total is the time since you pressed Start.
Can I use the stopwatch on my phone?
Yes. It works in any phone browser; keep the page open and the time stays exact even if the screen dims. Add it to your home screen to open it like an app.
Can I use it as a stopwatch for study sessions?
Yes. Start it when you sit down to study and press Lap at the end of each subject or break, so you can see where the time went.