Countdown
Hours 0–24, minutes and seconds 0–59; total duration 1 second to 24 hours. Enter an integer using only digits 0–9 in each field; no field may be empty.
Ready
Sound is off by default. After clicking to enable sound, you can test it; the browser may still block playback. The page always displays the time-up state, but background ringing is not guaranteed.
Stopwatch
Ready
Resetting the stopwatch clears all lap records, and they cannot be recovered.
No laps yet
| Lap | Total elapsed time | Interval |
|---|
While the stopwatch is running, you can record laps. Each entry shows the total time from the start to that entry and the interval since the previous entry. Paused time is excluded. At most 100 entries are retained.
Instructions for use
Set the duration, then start the countdown; after starting the stopwatch, you can record laps. Both run independently and can resume after a pause. Reset before changing the countdown duration.
Pause stops time from accumulating; resume continues from the paused point. Reset stops timing, returns the countdown to its configured duration, and returns the stopwatch to zero while clearing lap records.
Example: enter 0 hours, 1 minute and 30 seconds to count down from 00:01:30. Record stopwatch laps at 5 seconds and 8 seconds; their intervals are 5 seconds and 3 seconds respectively.
While running, elapsed time is calculated from differences in the device clock, not by counting screen refreshes. The display updates when you return to the page; changing the device clock may affect the result.
If the device clock is set back, the display may temporarily stop changing until the clock catches up.
The number of displayed decimal places does not represent actual timing precision.
MDN setTimeoutMDN Date.nowMDN Web AudioUses and limitations
The browser may suspend the page while it is in the background or the device is asleep, delaying sounds and time-up indications. Closing or reloading the page loses timing and lap records. Do not use it for important tasks that require an alert exactly on time.
Timing and laps are kept only in the current page’s memory, are not uploaded, and are not written to the URL or browser storage. Refreshing or closing the page loses the records.