World Clock and Global Time Zones: All 39 Standard Offsets at a Glance

TL;DR: There are only 38 standard UTC offsets actually in use worldwide (UTC−12:00 through UTC+14:00, plus a few half-hour and 45-minute steps). Add the UTC reference itself and you get the 39 cards on the World Clock page. Cities that share a time zone are merged onto one card, so one card equals one zone equals a batch of cities.

1. What the tool does

The World Clock page gathers the current time of the world time zones on a single screen, refreshes every second, and handles daylight saving automatically. It offers three views you can switch between:

There is also a city search at the top: type a city name, a zone name (e.g. Asia/Shanghai) or an offset (e.g. UTC+8) and the matching cities show up with their zone and a live clock face.

2. Why 39 time zones

Intuitively there seem to be hundreds of time zones (every country can pick its own), but counted by standard UTC offset there are only 38 steps in use: from UTC−12:00 (Baker Island, almost uninhabited) up to UTC+14:00 (Kiribati / Line Islands). Between them sit a few half-hour offsets (e.g. UTC+05:30 India, UTC+09:30 central Australia) and 45-minute offsets (e.g. UTC+05:45 Nepal, UTC+08:45 Eucla, Australia).

Add the UTC±00:00 reference itself (covering both Coordinated Universal Time and places like London or Lisbon) and you get the 39 cards on the page. In other words, those 39 cards already lay out every clock on Earth by offset — adding more would not add information, only split the same offset into more administrative zones.

Each card shows the zone IANA name, its standard offset, and a list of representative cities that share the zone (for example the UTC+08:00 card covers Beijing/Shanghai, Singapore, Perth and Hong Kong). This is the cities-in-the-same-zone-merged-onto-one-card design: one card shows one zone unified time, and lists all its representative cities.

3. How to use the three views

1. Clock view

One analog clock face per zone, the second hand moving every tick, with a digital time and local date below, plus a badge when daylight saving is in effect. The most intuitive view for seeing who is ahead.

2. List view

A table of city/region, current time and offset you can scroll through — good when you need an exact reading or to copy a time.

3. All-zones view

A static table ordered by standard offset, earliest to latest. Each row is a zone label, IANA name, standard offset and all representative cities. It does not tick every second, so it works as a world time-zone cheat sheet you can re-read any time.

4. City search: any city time on demand

Type a city name in the search box (Chinese or English, depending on the page language), or an IANA zone name, or an offset string, and the results list the matching cities — each with its own analog clock and digital time. Under each result we also list the other cities in the same zone, so you can confirm these cities are actually the same time.

For example, searching Tokyo gives you the current time of Asia/Tokyo and notes that Seoul and Pyongyang share the moment; searching UTC+8 lists every UTC+8 representative city at once: Beijing, Shanghai, Singapore, Hong Kong, Perth.

5. Why DST makes clocks jump

Many zones observe daylight saving (DST): once a year the clock jumps forward 1 hour (spring) and back 1 hour (autumn). So their current offset floats plus or minus 1 hour around the standard value. The offset badge and the card DST marker reflect this honestly — which is why Paris, nominally UTC+01:00, is actually UTC+02:00 in summer.

A common trap: in northern-hemisphere summer, New York (UTC−4) and London (UTC+1) are 5 hours apart; in winter New York (UTC−5) and London (UTC+0) are 6 hours apart. For cross-border meetings, always pin the date and the cities — never trust a time difference you memorized.

6. In practice: lining up a cross-border meeting

Say you are in Beijing (UTC+8) and need a three-way call with London (UTC+0/+1) and New York (UTC−5/−4):

1. Open the World Clock, switch to Clocks or List, and read the three cities faces directly;
2. Use city search to locate all three and confirm each one current offset (DST or not);
3. Pick a local time that works for all three (e.g. 8 PM Beijing), then use All-zones to read back London and New York local moments;
4. For an exact interval, use the Date Difference tool to compute the days / hours / minutes / seconds between two moments in your local zone.

7. FAQ

8. Summary

Open the World Clock tool and compare for yourself — it beats memorizing time differences.