Stopwatch
LED + analog stopwatch with laps and multi-lane mode
Live ranking (fastest first)
Space start/pause · L lap · R reset · F fullscreen · V cycle view · + add lane
About Stopwatch
What this stopwatch does
A browser-based stopwatch with a big seven-segment LED readout, an analog clock face, laps + splits, keyboard shortcuts, and fullscreen mode. Hit Add lane and it turns into a multi-stopwatch race timer — independent lanes, live ranking, and CSV export of every split.
Single-lane mode
- LED + analog views — flip between digital, analog, or both side-by-side
- Laps / splits with hundredths-of-a-second precision
- Fullscreen for big-screen workouts, classroom drills, or game shows
- Keyboard: Space start/pause, L lap, R reset, F fullscreen, V cycle view
- Survives reloads — labels and elapsed time persist in localStorage
Multi-lane (race timer) mode
Click Add lane to run any number of stopwatches at once. The same page handles:
- Independent lanes — start / pause / lap / reset each one individually
- Start all / Pause all so every lane begins at the gun together
- Label each lane (Alice, Lane 1, Pot A…) — labels show up in the CSV export
- Live ranking sorted fastest first with gold / silver / bronze highlight
- CSV export dumps every watch's elapsed time + every lap split
Common use cases
- Sport drills, classroom races, swim heats, debate rebuttals, cooking timers, exercise sets
- Time-and-motion studies (count cycle times across N stations)
- Game-show host's two-minute warning, or kids' chore challenges
Why this beats N tabs of a single-stopwatch site
Browser tab timers drift apart when the tab isn't focused, and merging the times afterwards is a chore. This page keeps every watch on the same event loop with the same persisted state, so the gap between two laps stays accurate to a hundredth of a second.
Frequently asked questions
Hundredth-of-a-second precision. Each watch uses the system wall-clock timestamp, so background tabs stay accurate.
Click "Add lane" once per competitor. Hit "Start all" (or press Space) at the gun to start every lane together, tap "Pause" on each lane as the competitor finishes, then "Export CSV" for the results.
There is no hard cap. Most laptops handle 20+ simultaneously without lag.
Yes. One row per lap with watch label, elapsed_ms, lap_number, split_ms, total_ms — plus one row per watch with no laps. Paste straight into Excel / Google Sheets.
Yes. Elapsed time is computed from the start timestamp, not a JavaScript counter, so background tabs stay accurate.
Labels and laps auto-save to your browser. Reload and you pick up where you left off.
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