Convert times across different time zones instantly
Current times in major cities around the world
Visualize time zones around the world
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Time zones are regions of the Earth that have the same standard time. There are 24 time zones, each generally 15 degrees of longitude wide, corresponding to one hour of time difference.
Daylight Saving Time Notice: Many regions observe Daylight Saving Time. When converting times, ensure you account for DST changes which typically occur in spring and fall.
Compare time differences between cities
| Time | London | Tokyo |
|---|---|---|
| Current Time | 5:00 PM | 1:00 AM |
| Time Difference | +9 hours | |
| Business Hours Overlap | 9:00 AM - 11:00 AM (GMT) | |
| Best Time for Meeting | 9:00 AM - 11:00 AM (GMT) | |
Current time in major global cities
Learn about time zones and their history
Before the 19th century, timekeeping was a purely local phenomenon. Each town would set its clocks to noon when the sun reached its highest point in the sky.
The need for standardized time zones became apparent with the expansion of railways and telecommunications. Sir Sandford Fleming proposed worldwide standard time zones in 1879.
In 1884, the International Meridian Conference divided the world into 24 time zones, each 15 degrees of longitude wide, with Greenwich, England as the prime meridian (0° longitude).
This system was gradually adopted by nations over the next several decades. The development of international air travel in the 20th century further solidified the importance of global time coordination.
Time zones are regions of the Earth that have the same standard time. The world is divided into 24 time zones, each generally 15 degrees of longitude wide.
Each time zone is defined by its offset from Coordinated Universal Time (UTC), ranging from UTC-12 to UTC+14. The International Date Line (IDL) marks the place where each day officially begins.
Many countries implement Daylight Saving Time (DST), adjusting clocks forward by one hour during summer months to extend evening daylight. However, DST is controversial and not observed in many parts of the world.
The actual implementation of time zones can be complex, with some countries using half-hour or quarter-hour offsets, and others spanning multiple geographical time zones but using a single time zone nationwide.
Managing global teams across multiple time zones presents challenges:
These challenges have led to the development of various tools and strategies for distributed teams, including asynchronous communication practices and flexible working hours.
Time zone differences also affect international business operations, financial markets, and global communications systems. Airlines and shipping companies must carefully coordinate schedules across time zones.
A: UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks and time. GMT (Greenwich Mean Time) is a time zone used in some European and African countries. UTC is more precise and is not affected by daylight saving time.
A: There are 24 primary time zones, each generally 15 degrees of longitude wide. However, due to political boundaries and daylight saving time variations, there are actually more than 24 time zone designations in use around the world.
A: Daylight Saving Time (DST) is the practice of setting clocks forward by one hour during warmer months to extend evening daylight. This typically begins in spring and ends in fall. Not all countries observe DST.
A: Use a time zone converter like this one to find overlapping business hours. Consider scheduling meetings during 9 AM to 11 AM in the latest time zone or 2 PM to 4 PM in the earliest time zone to find common availability.