Two timers on one page. The stopwatch measures elapsed time to the hundredth of a second, records laps (each lap's own time and the running total, called the split), labels the fastest and slowest lap in words, and exports the laps as a CSV file for a spreadsheet. The countdown runs up to six timers at once, each with its own label: start one with a single click on a preset (1, 3, 5, 10, 15, 25, 30 or 60 minutes) or set hours, minutes and seconds yourself. When a countdown reaches zero, an alarm sounds, the page says which timer ran out, the tab title changes, and the timer keeps counting the overtime so you can see how long ago it ended. Desktop notifications are available if you switch them on.
Nothing is uploaded or stored. Everything runs in your browser.
How to use the stopwatch
- Press Start (or the Space bar). Press Lap (or L) at each lap or checkpoint.
- Press Stop to pause; Resume continues from the same time. Reset (or R) clears the time and the laps.
- Give the session a name if you like; it becomes the CSV file name. Then Download CSV: each row has the lap number, lap time, split, both again in plain seconds for calculations, and a note for the fastest and slowest lap.
The keyboard shortcuts work when the focus is not in a text field or on a button, so typing a name never starts or resets the watch.
How to use the countdown
- Click a quick start time to start a timer straight away, or type hours, minutes and seconds (minutes and seconds may go above 59: 90 seconds is fine), add an optional label such as "Tea" or "Oven", and press Start timer.
- Each timer has Pause/Resume, +1 min and Reset, and a bin button to remove it.
- When time is up, press Stop to silence it and set it back to its full length, ready to run again.
Press Test sound once before you rely on the alarm: browsers only let a page play sound after a click, and a muted tab or a sleeping computer stays silent.
Why the times stay right in a background tab
A naive timer adds one second each time a once-a-second callback runs. Browsers delay those callbacks: a timer callback can run late when the page is busy, Firefox gives hidden tabs a minimum delay of one second, and Chrome can batch chained timers in a tab hidden for more than five minutes to once a minute. Counting callbacks then loses time. This tool never counts: the stopwatch stores when it started and the countdown stores when it will end, and the time shown is computed from the clock each time the page draws. A tab that was hidden for ten minutes shows the right time the moment you return. The alarm is scheduled in advance on the audio clock, which plays on time even while the page's timers are throttled. The article on timer accuracy in browsers explains the details and the arithmetic.
