Online stopwatch with laps

The short answer

An online stopwatch counts up from zero in your browser. Press Start or the space bar to begin, Lap or L to record a split, Stop to pause and Reset or R to clear. This one shows hundredths of a second, marks your best and worst laps, goes full screen and saves your laps as a CSV file.

How do you use the online stopwatch?

1. Press Start or the space bar. The time counts up in minutes, seconds and hundredths, and shows in your browser tab too.
2. Press Lap or L at the end of each lap, rep or round. The table lists every lap time and the total at that moment.
3. Press Stop or the space bar to pause. Start again to carry on from the same time.
4. Save your laps with Copy laps or Download CSV, then press Reset or R to go back to zero.

Stopwatch keyboard shortcuts

Stopwatch or timer: which one do you need?

A stopwatch counts up from zero and tells you how long something took. A timer counts down from a time you choose and tells you when to stop. Use the stopwatch when you want to measure; use the online countdown timer when you want an alarm at the end.

Ways to use a stopwatch for your habits

• Plank and wall-sit holds. Start when you get into position and stop when your form goes. Write the time down and try to add a few seconds each week, or make it a 30-day challenge.
• Walk and run splits. Press Lap at each lap of a track or each lamppost block. The best and worst laps show whether you started too fast. Turn your walk into distance with the steps to miles calculator.
• Reading sprints. Read for a lap, note the page, and press Lap. At the adult average of about 238 words per minute, ten minutes is about 2,400 words, or eight to ten pages of a typical paperback. Check your own pace with the reading speed test, then see how long your book will take with the reading time calculator.
• How long a task really takes. Time a chore or an email batch once. Real numbers make a to-do list honest; if a job takes more than a few minutes, give it a Pomodoro.
• Practice sessions. Time scales, drills or a language app and log the minutes in a habit tracker, so you see the total grow.

How accurate is this online stopwatch?

The stopwatch saves the moment you pressed Start, using your device's clock, and works out the elapsed time from it each time the screen redraws. It never counts ticks, so it stays right in a background tab, where browsers slow timers down to once a second or even once a minute, and after a reload, a closed tab or a sleeping laptop.

Browsers also offer performance.now(), a clock that never jumps when the system time changes. It is ideal for short measurements, but in several browsers it pauses while the computer sleeps, so for a stopwatch you might leave running for an hour the saved start time is the safer choice. Either way, the biggest error is how quickly you press the button.

Frequently asked questions

How do I use the online stopwatch?

Press Start, or the space bar on a keyboard. Press Lap (or L) each time you want a split; the table shows each lap and the running total. Press Stop to pause and Start to carry on, and Reset (or R) to go back to zero.

Does the stopwatch keep running if I switch tabs or close the page?

Yes. It saves the moment you pressed Start on your device, not a count of ticks, so a background tab, a sleeping laptop, a reload or closing and reopening the page all show the right time when you come back. Only Reset clears it.

What is the difference between a lap and a split?

A lap time is the time since the previous Lap press, for example one lap of a track. A split is the total time at that moment since Start. The table shows both: the Lap column and the Total column.

How accurate is an online stopwatch?

The clock reads your device's time to the millisecond and is shown in hundredths. The real limit is how quickly you press the button, the same as with a handheld stopwatch, so for races decided by hundredths use electronic timing.

Can I save or export my lap times?

Yes. Copy laps puts them on your clipboard as text, and Download CSV saves a file that opens in Excel, Numbers or Google Sheets, with the lap time and total for every lap.

Does it work full screen on a phone?

Yes. Press Full screen (or F) for digits that fill the screen. On iPhones, where web pages cannot use true full screen, the stopwatch fills the browser window instead. While it runs, it asks the screen to stay awake.

Sources and evidence

1. MDN Web Docs: performance.now() — performance.now() is a monotonic clock that is not affected by system clock changes, but in several browsers it pauses while the computer sleeps; for long timings Date.now() can be more practical.
2. MDN Web Docs: setTimeout(), timeouts in inactive tabs — Browsers slow down timers in background tabs, for example to once a second, and Chrome to once a minute after five minutes hidden.
3. MDN Web Docs: Screen Wake Lock API — A page can ask the screen to stay on; the lock is released when the page is hidden and must be asked for again when it is visible.
4. Brysbaert (2019): How many words do we read per minute? A review and meta-analysis of reading rate — Adults read English non-fiction silently at about 238 words per minute on average.

Updated September 27, 2026.