Meeting Planner

The world is divided into 24 primary time zones, each roughly 15 degrees of longitude wide, centered on the Prime Meridian (0°) in Greenwich, England. However, political boundaries cause many zones to deviate from strict longitude lines. Countries may adopt different offsets for economic integration, national unity, or historical reasons. The IANA Time Zone Database (tzdata) tracks these rules and is updated whenever governments change their time laws.

UTC as the Universal Reference

Coordinated Universal Time (UTC) is maintained by atomic clocks worldwide and serves as the stable backbone of global timekeeping. Unlike GMT, which is based on solar observation, UTC is precisely measurable and never changes for daylight saving time. Aviation, satellite operations, and internet protocols all rely on UTC to avoid ambiguity. For more, see the Wikipedia articles on Time zone and Coordinated Universal Time.

Convert specific times with our Timezone Converter, check live times worldwide with the World Clock, or count down to important events with our Countdown Timer. For work scheduling, try the Business Days Calculator.