Stopwatch
Space to start, space to stop. Laps, splits and milliseconds, with nothing to install.
Guide
How to use it
- Press Start or hit the space bar.
- Tap Lap (or press L) each time something completes, a length, a circuit, a question.
- The table shows each lap’s split, the running total and the gap to your best lap.
- Press Stop (space again) to freeze, Resume to continue, R to reset to zero.
- Use Full screen when it needs reading from across a room.
Examples
Where the laps earn their keep
Swim training: lap on every touch. Afterwards the splits show exactly where the pace sagged, length 14, usually.
Lap at the end of each exam question. The table becomes a map of which question types eat your time budget.
Settling household disputes with data: lap each kettle, fastest to a rolling boil wins. The best-lap column names the champion.
Method
How it works
Timing uses your browser’s monotonic performance clock, which counts steadily regardless of system clock changes, and the display refreshes about 30 times a second. When you stop and resume, elapsed time is carried over exactly.
Laps store the total at the moment you pressed lap, splits are the differences between consecutive laps, and the best split is highlighted as soon as you have two to compare.
FAQ
Frequently asked questions
How accurate is it?
The underlying clock is precise to well under a millisecond. Your reaction time pressing the buttons is the real margin of error, which is why laps beat mental notes.
What are the keyboard shortcuts?
Space starts and stops, L records a lap, R resets. They work whenever you are not typing in a text field.
Does it keep timing in a background tab?
Yes. The display may update less often while hidden, but the elapsed time is measured, not counted, so it stays exact.
What is the difference between split and total?
Split is the time for that lap alone, total is the time from the very start to that lap. Runners think in splits, race officials in totals.
Is there a time limit?
No practical one, it will happily run for hours. It survives tab switches, though closing the tab does reset it.
Can I export the laps?
Select the table and copy, it pastes cleanly into a spreadsheet, one lap per row.
More tools