World Clock
Current time in your location
Coordinated Universal Time
The global reference all time zones are based on
Understanding World Time Zones
A world clock displays the current local time in multiple cities and time zones simultaneously. This is essential for international business, travel planning, and staying connected with people in different parts of the world. Our world clock covers 31 major cities across every continent, updated live every second.
Time zones were standardized in 1884 at the International Meridian Conference in Washington, D.C., where Greenwich, England was chosen as the prime meridian (0° longitude). From there, the world is divided into zones roughly 15° apart, each one hour ahead or behind the next. In practice, time zone boundaries follow national and regional borders rather than strict longitude lines, which is why countries like China use a single time zone (UTC+8) across a landmass spanning five geographical zones.
Daylight Saving Time adds further complexity. Over 70 countries shift their clocks forward by one hour during warmer months, meaning the offset between two cities can change twice a year. For example, the difference between New York and London is normally 5 hours, but it briefly becomes 4 hours in spring when the UK moves to BST before the US shifts to EDT, and again in autumn when the transition happens in reverse.
The green, amber, and gray indicators on each city card show whether it is currently business hours, daytime, or nighttime in that location. This makes it easy to find the right time to schedule a call, send a message, or plan a meeting with colleagues in other time zones.
Frequently Asked Questions
How accurate is this online world clock?
The clock reads your device's system time via the browser's Intl API. Modern operating systems sync automatically with NTP (Network Time Protocol) servers, so the time shown is typically accurate to within a few milliseconds of the official atomic clock time.
What is the difference between UTC and GMT?
UTC (Coordinated Universal Time) and GMT (Greenwich Mean Time) show the same time in practice — both represent the time at 0° longitude. However, UTC is the modern standard maintained by a network of atomic clocks worldwide, while GMT is the historic time zone tied to the Royal Observatory in Greenwich, London. UTC is used in aviation, computing, and science; GMT persists mainly as a colloquial term.
How many time zones are there in the world?
While there are 24 standard hourly zones, over 38 time zones exist in practice. Several countries use half-hour or quarter-hour offsets: India operates on UTC+5:30, Iran on UTC+3:30, Nepal on UTC+5:45, and the Chatham Islands on UTC+12:45. The full range runs from UTC−12:00 (Baker Island) to UTC+14:00 (Kiribati).
Which city enters the new day first?
Kiritimati (Christmas Island) in the Republic of Kiribati, at UTC+14, is the first inhabited place to enter each new calendar day. Among major cities, Auckland, New Zealand (UTC+12 or UTC+13 during DST) is typically the first to see a new day. At the other end, American Samoa and Baker Island (UTC−11 and UTC−12) are the last places on Earth where each day ends.
What do the colored status indicators mean?
The green dot means it is currently business hours (9:00 AM – 5:00 PM) in that city — a good time to call or schedule meetings. The amber dot means it is daytime (6:00 AM – 9:00 PM) — the person is likely awake. The gray dot indicates nighttime (9:00 PM – 6:00 AM) — avoid scheduling calls unless urgent.
What is the International Date Line?
The International Date Line (IDL) runs through the Pacific Ocean roughly along 180° longitude, with deviations to keep island nations and territories within a single date. When you cross it traveling westward, the calendar date advances by one day. Traveling eastward, the date goes back one day. This is why it is possible for Auckland to be on Tuesday while Honolulu is still on Monday.