How the conversion works
Your date and time are read in the source zone and turned into one exact moment (a UTC instant). That moment is then shown in every other zone using the zone's rules for that date, so daylight saving time is applied only when it is in force.
Things that trip people up
- Daylight saving changes on different dates. The US and Europe switch on different weekends, so the gap between New York and Madrid is sometimes 5 hours and sometimes 6.
- Not every place shifts. India, Japan and most of Asia and Africa stay on one offset all year.
- Half-hour offsets exist, such as UTC+05:30 in India.
- Skipped and repeated hours. A local time that does not exist because clocks jumped forward is resolved to the hour before the change.
Zone names such as Europe/Madrid come from the IANA time zone database, built into your browser. For a live view use the world clock.