Time Zone Converter

How Does the Time Zone Converter Work?

Select a date and time, choose your source time zone ("From"), and the destination time zone ("To"). The converter automatically accounts for daylight saving time (DST) based on the specific date, so you always get an accurate conversion — whether it's summer or winter.

Popular Time Zone Conversions

Understanding Time Zones

Time zones divide the Earth into 24 vertical slices, each nominally 15 degrees of longitude wide — one hour apart. The system originated from the practical need to coordinate railway schedules in the 19th century. Before standardization, each city kept its own local solar time, meaning a traveler crossing the United States by train would need to reset their watch dozens of times. The Greenwich Meridian (0°) was established as the prime meridian in 1884, and the UTC (Coordinated Universal Time) offset system used today developed from Greenwich Mean Time (GMT).

In practice, time zone boundaries don't follow straight longitude lines — they're drawn around political borders, national territories, and geographic features to keep entire countries or regions on the same time. This is why China, which spans 5 geographic time zones, uses a single time zone (UTC+8), and why India uses a half-hour offset (UTC+5:30) to split the difference between two zones. There are currently about 38 distinct UTC offsets in use worldwide, not the neat 24 that simple longitude arithmetic would suggest.

Daylight Saving Time: Who Observes It and Why

Daylight Saving Time (DST) shifts clocks forward by one hour in spring and back in fall, extending evening daylight during summer months. The United States observes DST from the second Sunday in March to the first Sunday in November. The European Union observes it from the last Sunday in March to the last Sunday in October — which means there's a brief period each spring and fall when the US/EU time difference is one hour different from the rest of the year.

About 70 countries observe DST; another 100+ do not. Countries near the equator — where day length doesn't change significantly with the seasons — generally skip DST entirely. Arizona (within the US) does not observe DST, except for the Navajo Nation within its borders. The EU voted to end mandatory DST in 2019, but implementation has been delayed; as of 2026, EU countries still observe it.

When scheduling international meetings or flights, always account for DST status in both locations. A meeting scheduled for "9 AM New York, 2 PM London" during summer may become "9 AM New York, 3 PM London" during winter — because the US clocks change on a different date than UK clocks, briefly creating a 6-hour rather than 5-hour difference.

UTC, GMT, and the Global Reference

UTC (Coordinated Universal Time) is the global time standard used by aviation, maritime, computing, and scientific applications. It replaced GMT as the world's time reference in 1972. The two are practically equivalent for most purposes — UTC is based on atomic clocks while GMT is based on Earth's rotation — but UTC is the authoritative standard. Computer systems record timestamps in UTC and convert to local time for display.

Time zones are expressed as UTC offsets: New York in winter is UTC−5 (Eastern Standard Time); Paris in summer is UTC+2 (Central European Summer Time). Knowing a location's UTC offset makes it easy to calculate the difference between any two zones: New York (UTC−5) to Tokyo (UTC+9) is a 14-hour difference — if it's 9 AM Monday in New York, it's 11 PM Monday in Tokyo.