What does this calculator do?
It takes a date and time in one city and tells you what the clock reads at that same moment in another city — useful for booking calls or flights across the world.
// physics › Clock & Calendar
Time Zone Converter
Convert a date and time from one city's zone to another, with daylight saving handled automatically.
same moment, different local clock
Frequently asked questions
Does it handle daylight saving time?
Yes, automatically. It uses the world time-zone database, which knows when each place switches to summer time, so the conversion is correct for the exact date you pick — not just a fixed offset.
Can you show an example?
9:00 in the morning in Sydney on 1 June 2026 is just after midnight in London that same day (London is on summer time then, UTC+1). The tool shows the converted time and the offset from UTC.
Why does the date sometimes change?
Because zones can be many hours apart. If converting pushes the time past midnight, the calendar date shifts to the day before or after — which is why a call can land 'tomorrow' for the other person.
How do I enter the time?
Pick the two cities from the list, then type the date as YYYY-MM-DD and the time as HH:MM in 24-hour form (for example 14:30 for half past two in the afternoon).
What does UTC mean?
UTC is the world's reference time (roughly the time in London in winter). Every zone is described as an offset from UTC — for example UTC+10 is ten hours ahead. The result shows the target city's offset so you can see the difference.