00:00.00
Lap 1: 00:00.00
Space start / stop L lap R reset
Laps
Laps
0
Average lap
–
Fastest
–
Slowest
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| # | Lap time | Total | vs fastest |
|---|---|---|---|
| Press Lap while the stopwatch is running to record a split. | |||
fastest lap slowest lap
Start, stop, and record laps to the hundredth of a second, with fastest, slowest, and average lap worked out for you.
| # | Lap time | Total | vs fastest |
|---|---|---|---|
| Press Lap while the stopwatch is running to record a split. | |||
This stopwatch measures elapsed time to the hundredth of a second and records laps with a single key press. It suits track and swim practice, interval workouts, cooking steps, speed runs, timing presentations, or any task where you want split times rather than a single total. Each lap shows its own duration, the running total at that moment, and how far it was from your fastest lap; the fastest and slowest laps are highlighted and the average lap is computed as you go. Laps can be copied as text or downloaded as a CSV file for a spreadsheet.
When you press Start, the stopwatch stores the system clock time. On every animation frame it computes elapsed time as the current clock minus that start time, plus any time accumulated before earlier pauses, so it stays accurate even if the browser throttles a background tab. Pressing Lap records the current total; each lap's duration is the difference between consecutive totals. Statistics are derived from the lap durations: fastest is the minimum, slowest the maximum, and average is the sum divided by the lap count. The display shows minutes, seconds, and centiseconds, adding an hours field once elapsed time reaches one hour.
It reads the system clock in milliseconds and displays hundredths of a second, so timing is limited mainly by your reaction time on the button or key, which is usually 150 to 300 milliseconds. The clock itself does not drift while the tab is in the background because elapsed time is recalculated from the start time rather than counted in ticks.
Lap time is how long that particular segment took, measured from the previous lap press (or from Start for the first lap). Total is the stopwatch reading at the moment you pressed Lap. The delta column shows how much slower each lap was than your fastest lap; the fastest lap shows +0.00.
Space starts and stops the stopwatch, L records a lap while it is running, and R resets everything. The shortcuts are ignored while your cursor is inside a text field, so they will not fire accidentally while you type elsewhere on the page.
Yes. Copy laps puts a plain-text table on your clipboard, and Download CSV saves a file with lap number, lap time, total time, and both values in milliseconds, which opens directly in Excel, Google Sheets, or Numbers. The data lives only in this page; reloading the page clears it.
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