A stopwatch that reads to the hundredth of a second, records laps and splits as you go, and totals everything in a table — built on timestamps, so a background tab cannot make it drift.
| Lap | Lap time | Total time |
|---|
The stopwatch never adds up ticks. When you press Start it records the current timestamp; the display is always now − start time (plus whatever had accumulated before a pause). The screen redraws on the browser’s animation frame, but the value itself comes from the clock, so throttling in a background tab changes how often you see updates — never the number itself. The moment the tab is visible again, the display is exact.
Each Lap press stores the total elapsed time at that instant. A lap’s own time is the difference between its total and the previous lap’s total, which is how coaches’ split tables have always worked.
Count down instead of up: preset minutes, progress ring and a loud alarm at zero.
Free — try itTimed work and rest rounds for workouts, sparring and circuit training.
Free — try itAlternate 25-minute focus sessions with breaks, counted automatically.
Free — try itTotal up to four clock-in/clock-out pairs in a day into paid time.
Free — try itThe underlying time comes from your device clock with millisecond resolution, and the display shows hundredths of a second. Human reaction time on the Start and Stop buttons (typically 150–250 ms) is a far bigger factor than any timing error in the page.
The split is the total elapsed time when you pressed Lap; the lap time is just that one lap — the split minus the previous split. The table shows both, newest lap first, and marks your fastest and slowest laps once you have at least two.
Yes. Because the elapsed time is computed from timestamps, switching tabs does not slow it down. The on-screen digits refresh less often while the tab is hidden (browsers save battery that way), but the value is exact the moment you return.
Effectively as long as the tab stays open — hours roll over into the display after 59:59.99. Closing the tab discards the run and its laps, so copy the table first if you need the record.
The lap table is plain page content: select it and copy it into a spreadsheet, or use your browser’s print command to save the page as a PDF with the table included.
Every number on this page is one subtraction away from the clock:
A runner presses Start, then Lap at the end of each 400 m circuit. The splits read 1:32.40, 3:01.85 and 4:35.10. The lap times are therefore 1:32.40, then 3:01.85 − 1:32.40 = 1:29.45, then 4:35.10 − 3:01.85 = 1:33.25 — so the table marks lap 2 as fastest and lap 3 as slowest, and the stopwatch total is 4:35.10. Those are exactly the numbers the table above produces from the same three Lap presses.
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