How accurate is this stopwatch?

It reads your device's high-resolution clock and repaints every animation frame, so the display is honest to the millisecond. Over very long runs it cannot drift the way a tick-counting timer can, because every reading is measured from the real start time rather than accumulated from intervals.

Each Lap press adds a row with that lap's own duration and the total elapsed time at the moment you pressed it — the standard split format coaches use, so you can compare lap 3 against lap 7 directly.

Does it keep running if I switch tabs?

Yes. The clock is based on real timestamps, not screen updates, so time keeps counting correctly in a background tab; the display catches up the moment you return. Like every browser tab it stops if the browser itself is fully closed.

Can I run it alongside the countdown timer?

Open the Timer page in a second tab — each tab keeps its own clock. Handy for intervals: stopwatch counting up in one tab, rest countdown in the other.

Online Stopwatch

Millisecond timing with laps — for workouts, cooking, speedruns, study sprints and anything else measured honestly.

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How to use it

Press Start — the clock runs from your device's high-resolution timer, shown to the millisecond.

Press Lap at every split. Each lap records its own duration and the running total.

Pause anytime and resume where you left off; Reset clears the clock and the lap list.

Why a real stopwatch beats counting

Counting seconds in your head drifts with your attention; a phone's built-in timer app buries the stopwatch behind menus and lock screens. This one is a single page with three buttons and a big honest readout, designed to live in a spare tab: runners checking kilometre splits, students timing practice questions, cooks watching a reduction, developers timing a slow query. The lap table is the point — totals tell you how long the whole thing took, but laps tell you where the time went.

Online Stopwatch

How to use it

Why a real stopwatch beats counting

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