Stopwatch
Stopwatches fail in two familiar ways: they drift in background tabs, and they reset when the page reloads. This one fixes both - elapsed time comes from timestamp arithmetic (start time plus accumulated time, never tick counting), and the running state persists to local storage, so an accidental refresh mid-run restores the stopwatch still running with its laps intact.
Lap records both the split and the cumulative total, which is what you actually need for interval training, brewing timers, lab work or timing speakers. While running, the tab title shows elapsed time, letting you monitor a run from another window. Precision is 10 milliseconds - honest, since browser rendering rarely justifies more.
How to use
- Press Start; the display and the tab title begin counting immediately.
- Press Lap at each split - laps list both split time and running total; Stop freezes, Start resumes without zeroing.
- Reset clears everything. Reload the page mid-run and the stopwatch comes back still running.
Frequently asked questions
How precise is it?
10 milliseconds, shown as hundredths. Under the hood it uses millisecond timestamps, so timing is accurate to the clock; the display simply rounds to hundredths - the same resolution physical stopwatches advertise.
What happens if I reload or close the tab?
Reload mid-run: state restores and timing continues seamlessly, because elapsed time is computed from the saved start timestamp. Close the tab entirely: the frozen total is remembered, and reopening the page shows the stopped stopwatch where you left it.
How do lap splits work?
Each Lap press stores the time since the previous lap (the split) and since Start (the total). For a 4x400 workout that means you see each lap's own time and the session total - no manual subtraction.
Can I time something while using other apps?
Yes - that is the tab-title feature. Switch windows and the running time stays visible in the browser tab; throttling may refresh it at one-second steps in the background, but the underlying timestamp math stays exact.