What this tool does
Provides a countdown timer and an elapsed-time stopwatch in the current browser tab, with start, pause and reset controls.
How to use it
- Choose timer or stopwatch mode.
- Enter minutes and seconds, then start. A new start after completion uses the current inputs; a paused timer resumes its remaining time.
- Start, pause when needed, and keep the tab available until finished.
- Choose a 1, 5, 10 or 25 minute preset, or enter a duration. Presets stop the current session without starting a new one.
- Sound is off by default. Use Test sound, then enable the completion sound if wanted. A persistent completion message appears at zero.
- In stopwatch mode, record splits and cumulative times in whole seconds, up to 100 laps. Reset or a mode change clears the list; same-second duplicates are disabled.
- Focus view enlarges the current clock and controls. Closing it or pressing Escape preserves the session; it does not prevent sleep.
Method
While running, elapsed seconds are calculated from Date.now rather than merely counting display ticks. The display refreshes about four times per second but shows whole seconds. Timer mode stops at zero; stopwatch mode continues upward until paused.
Worked example
Set five minutes, reset, and start. After pausing at approximately 03:40 remaining, starting again continues from that stored remainder rather than the original five minutes.
Common uses
- Study or break intervals
- Cooking reminders while the tab stays open
- Measuring a short task
Limitations
The optional short tone requires browser audio support and permission to play. Actual sound and on-time alerts are not guaranteed. No OS notification or background service is provided. Closing or reloading loses the session; sleep and inactive-tab throttling can delay updates. Do not use for medication, safety, laboratory or other critical timing. Editing minutes or seconds preserves a running or paused duration; Reset or a preset replaces it.
FAQ
Will it keep running after I close the tab?
No. State is held only by the open page and is not restored after closing or reloading.
Why can the display update late?
Browsers may throttle inactive tabs or pause work while the device sleeps.