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Online Stopwatch

Free

Free online stopwatch with lap times, split recording, and keyboard shortcuts. Runs in your browser tab — no app, no download needed.

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Settings guide

Keyboard shortcuts:

KeyAction
SpaceStart / Stop
LRecord lap
RReset

Lap vs split: A lap records the time for that specific interval (the time since the previous lap). A split records cumulative elapsed time. This stopwatch records both for each lap press.

Background accuracy: The stopwatch uses performance.now() for high-resolution timing and Date.now() as an anchor to maintain accuracy when the tab is backgrounded. Modern browsers throttle setInterval in background tabs, but the displayed time on return is always computed from the anchor timestamp, not from interval tick count — so the displayed time remains accurate.

Printing lap records: After recording laps, use your browser's Print function (Ctrl/Cmd + P) to print the lap table, or select all and copy to paste into a spreadsheet.

Format comparison

vs your phone's stopwatch app: A phone stopwatch is always accessible if your phone is in reach. An online stopwatch is better when you are already at a computer and switching to your phone would break your workflow. It is also useful in settings where phones are restricted (exam rooms, lab environments, some workplaces).

vs a physical stopwatch: Physical stopwatches are required in some athletic and scientific contexts (official timing, anti-radio environments). For everyday use, a browser stopwatch is more convenient: always synced, always charged, and the lap data can be copied to a document.

vs a countdown timer: A stopwatch measures elapsed time from zero upward; a countdown timer measures remaining time from a set duration downward. Use a stopwatch when you want to know how long something took. Use a countdown when you need to be alerted when a specific duration has passed.

How it works

1

Press Start or hit Space

The timer begins counting from 00:00:00.00 with millisecond precision.

2

Record laps

Press L or the Lap button to record split times without stopping the main clock.

3

Stop and review

Press Stop when finished. Review lap times in the table below the timer. Copy or print the results.

About this format

An online stopwatch is the fastest timing tool you have access to right now. Open a browser tab, navigate here, and you are timing. No app install, no account, no loading screen. The stopwatch starts the moment you press the button.

Browser-based stopwatches have one important advantage over phone stopwatch apps: they run in the background across tabs. Start the timer on this tab, switch to your work, and the clock keeps running. Come back ten minutes later and the elapsed time is exactly right. Phone apps can be paused by the OS when they go to background; a browser timer running JavaScript is not subject to the same suspension in the same way.

This stopwatch is useful for any timed activity: cooking intervals, workout sets, coding sessions, meeting durations, reading time checks, exam practice, lab timing, or any other activity where you need elapsed time without the friction of finding and launching an app.

Lap recording captures split times without stopping — press the lap button to mark intervals while the main timer continues. Keyboard shortcuts let you control the stopwatch without taking your hands off your keyboard: Space to start/stop, L to record a lap, R to reset.

Frequently asked questions

Does an online stopwatch work when I switch tabs?+
Yes. The stopwatch records the absolute start timestamp when you press Start. When you return to the tab, the elapsed time is computed from that timestamp to the current time — not from interval tick counts. Even if the browser throttled background timers, the displayed time is always correct. The only exception is if the browser suspends the tab entirely, which can happen on mobile browsers after extended backgrounding.
How accurate is a browser-based stopwatch?+
Browser stopwatches use the Performance API with sub-millisecond resolution in modern browsers. The display typically shows hundredths of a second. For everyday use — cooking, workouts, meetings, study sessions — this accuracy is more than sufficient. For professional athletic timing (official race results) or scientific measurements requiring microsecond precision, certified hardware timers are the appropriate tool.
Can I use a stopwatch during an online exam?+
Yes, in most cases. A browser-based stopwatch runs in a separate tab and does not interfere with the exam interface. However, some proctored exam platforms lock the browser using fullscreen enforcement or kiosk mode, preventing you from switching tabs. Check your exam platform's rules. If tab switching is restricted, use a physical watch or a second device running the stopwatch instead.
What is the difference between a lap and a split?+
A split is the cumulative elapsed time at the moment you press the lap button — measured from start to that point. A lap is the time for that specific interval — measured from the previous lap press to the current one. If you press lap at 0:30 and again at 1:10, the second split is 1:10 and the second lap is 0:40. Both are recorded for each lap press.
Can I share my lap results with someone else?+
The stopwatch does not generate a shareable URL for lap results. To share your timing data, select all rows in the lap table and copy them (Ctrl/Cmd + A, then Ctrl/Cmd + C), then paste into an email, spreadsheet, or message. Alternatively, use your browser's Print function to create a PDF of the lap table that can be shared.

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