Convert time between different time zones worldwide. Calculate time differences, handle daylight saving time, and schedule international meetings with accurate time zone conversions.
Time zone conversion is the process of calculating what time it is in one location when you know the time in another location. This is essential for coordinating international meetings, scheduling calls across continents, planning travel, and managing global teams.
Time zones are regions of Earth that have the same standard time. They are defined by their offset from Coordinated Universal Time (UTC), which serves as the global time standard. For example, Eastern Standard Time (EST) is UTC-5, meaning it is 5 hours behind UTC.
Determine the UTC offset for both the source and target time zones. For example, New York (EST) is UTC-5, while London (GMT) is UTC+0.
Subtract the source offset from the target offset to find the time difference. London (UTC+0) minus New York (UTC-5) equals +5 hours.
Add or subtract the time difference from your source time. If it's 10:00 AM in New York, add 5 hours to get 3:00 PM in London.
Check if either location observes Daylight Saving Time and adjust accordingly. DST typically adds 1 hour during summer months.
| Time Zone | Abbreviation | UTC Offset (Standard) | UTC Offset (DST) | Major Cities |
|---|---|---|---|---|
| Pacific Time | PST/PDT | UTC-8 | UTC-7 | Los Angeles, San Francisco, Seattle |
| Mountain Time | MST/MDT | UTC-7 | UTC-6 | Denver, Phoenix, Salt Lake City |
| Central Time | CST/CDT | UTC-6 | UTC-5 | Chicago, Houston, Mexico City |
| Eastern Time | EST/EDT | UTC-5 | UTC-4 | New York, Toronto, Miami |
| Greenwich Mean Time | GMT/BST | UTC+0 | UTC+1 | London, Dublin, Lisbon |
| Central European Time | CET/CEST | UTC+1 | UTC+2 | Paris, Berlin, Rome |
| Eastern European Time | EET/EEST | UTC+2 | UTC+3 | Athens, Cairo, Helsinki |
| India Standard Time | IST | UTC+5:30 | No DST | Mumbai, Delhi, Bangalore |
| China Standard Time | CST | UTC+8 | No DST | Beijing, Shanghai, Hong Kong |
| Japan Standard Time | JST | UTC+9 | No DST | Tokyo, Osaka, Seoul |
| Australian Eastern Time | AEST/AEDT | UTC+10 | UTC+11 | Sydney, Melbourne, Brisbane |
Daylight Saving Time is the practice of advancing clocks during warmer months so that darkness falls at a later clock time. Most regions that observe DST move clocks forward by one hour in spring ("spring forward") and back by one hour in autumn ("fall back").
Scenario: Schedule a meeting for team members in New York, London, and Tokyo
New York (EST): 9:00 AM (UTC-5)
London (GMT): 2:00 PM (UTC+0) - 5 hours ahead
Tokyo (JST): 11:00 PM (UTC+9) - 14 hours ahead
Result: 9:00 AM EST works for New York and London but is late evening for Tokyo. Consider rotating meeting times to accommodate all time zones fairly.
Scenario: Flight departs Los Angeles at 11:00 PM PST with 11-hour flight duration to London
Departure: 11:00 PM PST (UTC-8)
Flight Duration: 11 hours
Calculation: 11:00 PM + 11 hours = 10:00 AM next day PST
Convert to London (GMT, UTC+0): 10:00 AM PST + 8 hours = 6:00 PM GMT
Result: You arrive in London at 6:00 PM local time, despite the flight taking 11 hours.
Scenario: Track when major stock exchanges are open
NYSE (New York): 9:30 AM - 4:00 PM EST
In London (GMT): 2:30 PM - 9:00 PM
In Tokyo (JST): 11:30 PM - 6:00 AM next day
In Sydney (AEDT): 1:30 AM - 8:00 AM next day
Result: Understanding these conversions helps traders in different time zones know when they can trade on the NYSE.
Scenario: Weekly meeting scheduled for 10:00 AM EST during DST transition
Before DST (EST): 10:00 AM EST = 3:00 PM GMT (5-hour difference)
After DST (EDT): 10:00 AM EDT = 2:00 PM BST (4-hour difference)
Result: When both regions change to DST, the time difference remains 5 hours, but if only one changes, the meeting time shifts by 1 hour for participants in the other zone. Always verify meeting times around DST transitions.
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