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Stopwatch

A precise online stopwatch with lap times.

00:00.00

Keyboard: Space start/stop · L lap · R reset

When to use it

The online stopwatch measures elapsed time to a hundredth of a second, with laps. Use it to time runs, swimming lengths or interval workouts, speeches and presentation rehearsals, science experiments, cooking steps, games, or how long a task really takes you. It works on phones, tablets and computers without installing anything.

How to use the stopwatch

  1. Press Start. The display counts up in minutes, seconds and hundredths.
  2. Press Lap to record a split without stopping. Each lap appears in the table with its Lap time and the running Total.
  3. Press Stop (the same button) to pause, and Start again to continue.
  4. When the stopwatch is stopped, the Lap button becomes Reset: press it to clear the time and laps.
  5. Press Copy laps to copy the results as text.

Keyboard: Space starts or stops, L records a lap, and R resets.

A worked example

You’re running four laps of a 400 m track. Start the stopwatch at the line and press Lap each time you pass it. Your laps come out as 1:52.40, 1:55.10, 1:58.75 and 1:50.20, for a total of 7:36.45. The last lap is highlighted green as your fastest and the third red as your slowest, showing you slowed in the middle and finished strong. Copy the laps into your training log.

Ideas for using laps

  • Interval training: record each work and rest period.
  • Presentation practice: press Lap at each new slide to see which sections run long.
  • Study sessions: lap at the end of each task to see where time goes.
  • Classroom experiments: record repeated trials and copy them into a spreadsheet.
  • Board games: time each player’s turn.

Tips

  • Use the keyboard on a laptop; Space and L are quicker and more precise than clicking.
  • Put your phone where you can tap it easily for workouts, and keep the screen on.
  • Copy laps before resetting, because reset clears them.
  • For counting down instead of up, use the Countdown Timer.

Common mistakes

  • Pressing Reset instead of Lap in a hurry. Reset only works when stopped, which helps avoid this.
  • Starting late. Get your finger ready on the button or Space bar before the event begins.
  • Relying on it for official records. Human reaction time adds about 0.2 seconds; races use electronic timing.

Private by design

Everything runs in your browser. No data is sent anywhere.

Count down from a set time with the Countdown Timer, set a clock-time reminder with the Alarm Clock, or study in focused blocks with the Pomodoro Timer.

Frequently asked questions

How accurate is this stopwatch?

It measures time with your device's high-precision clock and shows hundredths of a second. It keeps counting correctly even if you switch tabs, because it works out elapsed time from the clock rather than counting ticks.

Can I use it with the keyboard?

Yes. Press Space to start or stop, L to record a lap, and R to reset. That's handy for timing without looking at the screen.

What are lap time and total?

Lap time is how long that single lap took. Total is the overall time on the stopwatch when you pressed Lap. With three or more laps, the fastest is shown in green and the slowest in red.

Will it keep running if my phone's screen turns off?

Elapsed time stays correct when you come back, because it's based on the clock. Some phones pause web pages in the background, but the time catches up as soon as you return.

How do I save my lap times?

Press Copy laps and paste them into a note, message or spreadsheet. They're copied as text with lap number, lap time and total.

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