Stopwatch

    Precise online stopwatch with lap timer. Millisecond accuracy for sports, workouts, and timing anything.

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    Read the complete guide for in-depth tips and troubleshooting.

    What Is an Online Stopwatch?

    An online stopwatch counts elapsed time upward with large digits visible across a room. Coaches, teachers, and labs use it when everyone needs to see the same clock. Free, instant, and works on any device with a browser.

    How to Use the Stopwatch

    1. Press Start at the beginning of your activity
    2. Enter fullscreen for group visibility
    3. Press Stop to freeze elapsed time
    4. Reset for the next trial or lap
    5. Keep the browser tab active for accurate timing

    Stopwatch Use Cases

    Sports drills

    Sprint and lap timing

    Science labs

    Class-visible experiment timing

    Speed challenges

    Competitions and games

    Cooking experiments

    Track how long something has simmered

    Public speaking practice

    Measure rehearsal length

    Manufacturing

    Quick workstation timing

    Related Tools

    Countdown TimerHIIT TimerPomodoroDigital Clock

    Frequently Asked Questions

    How do I use the online stopwatch?

    Click Start to begin timing. Click Stop to pause, then Resume to continue or Reset to clear. While running, click Lap to record a split time without stopping the main timer. Lap times appear in the list below, with the best lap highlighted in green and the worst in red.

    How accurate is this stopwatch?

    This stopwatch uses the browser's requestAnimationFrame API for smooth updates and Date.now() for precise time measurement, giving millisecond-level accuracy. It's accurate enough for sports timing, cooking, and most everyday uses.

    What is a lap time?

    A lap time (or split time) records the elapsed time at a specific moment without stopping the stopwatch. Each lap shows both the split time (time since the last lap) and the total elapsed time. This is useful for tracking individual intervals in a race or workout.

    Does the stopwatch keep running if I switch tabs?

    Yes. The stopwatch continues running even if you switch to another browser tab. The time is calculated based on the actual elapsed wall-clock time, not animation frames, so it remains accurate even when the tab is in the background.

    Can I use this stopwatch on my phone?

    Yes. The stopwatch works on all devices including smartphones and tablets. The interface is fully responsive and touch-friendly. Tap Start, Stop, Lap, and Reset just as you would click them on a desktop.