What is a time zone calculator?
A time zone calculator converts a date and time in one location into the matching date and time in another. It is useful for scheduling meetings, planning travel, working with remote teams and coordinating across countries.
How time zone conversion works
The entered date and time are treated as local time in the source time zone, converted to a UTC instant, then displayed in the target time zone. This avoids fixed-offset mistakes and accounts for daylight saving time.
What is UTC and why it matters
UTC is the global reference time used to compare time zones. Time zone conversion works reliably by converting a local time to UTC first, then converting that UTC instant into the destination time zone.
What is daylight saving time (DST)?
Daylight saving time is the practice of moving clocks forward for part of the year. Some regions use DST and some do not, which means the difference between two cities can change depending on the date.
Why time differences change during the year
Time differences change because countries start and end DST on different dates, and some countries do not change clocks at all. London to New York is typically 5 hours, but the exact offset should always be checked for the specific date.
How to schedule meetings across time zones
Choose the meeting date, enter the organiser's local time, then convert it to each participant's time zone. Check whether the result falls on the previous or next day before sending calendar invitations.
Common global time differences
London to New York is typically 5 hours difference. London to Tokyo is typically 9 hours ahead. New York to Los Angeles is 3 hours difference. These examples can shift around DST transition dates, so use the calculator for the exact day.