How to use the online timer
A timer in seconds suits very short actions, holds and work-rest changes. Enter the interval when the activity begins, then check remaining time without converting units in your head. A countdown measures elapsed time, so it continues consistently across a daylight saving change.
For shared starts, add the zone separately. AEST, AEDT, ACST, ACDT and AWST can produce different local readings, and not every state changes clocks. The unit controls duration only; transport timetables, school calendars and public-holiday dates need a current source.
Choose an alert appropriate for the setting and check that device volume, power and sleep settings will let it sound.