About the World Clock
This world clock shows the live local time in more than 30 major cities across every continent, side by side, with each city’s UTC offset and how far ahead or behind your own time it is. Add the cities you care about — where your team, family or customers are — and the list is remembered on this device.
Below the live clocks, the time converter answers “what time will it be in Tokyo when it is 9 AM in New York?” for any date. Because it uses each city’s real time-zone rules, daylight saving changes are handled automatically, and it shows how many normal 9-to-5 working hours two cities share — useful for scheduling calls and meetings.
It is built for remote teams, travellers, traders watching market opens and anyone with friends abroad. Times come from the time-zone database built into your browser, the same data used by phones and operating systems.
How to use the world clock
- 1Watch the live clocks, and add or remove cities to build your own list.
- 2To convert a time, pick your city, the date and the local time.
- 3Choose the city you want to compare with.
- 4Read the local time there, the difference in hours and the shared working hours.
- 5Scroll the table to see the same moment in every city.
Formula and method
Every city keeps a time-zone offset from Coordinated Universal Time (UTC). The world clock first converts your city’s local time to UTC using your zone’s offset on that date, then adds each other city’s offset at that same instant. Offsets come from the IANA time-zone database, so daylight saving time is applied only when and where it is actually in force.
The time difference between two cities is the difference between their offsets and can change during the year: New York and London are usually 5 hours apart, but only 4 for two to three weeks in March and about one week around the end of October, when the US has changed its clocks and the UK has not yet (or vice versa). Shared working hours assume both cities work 9 AM to 5 PM local time.
Worked examples
9 AM in New York → London
On 29 September 2026 New York is on EDT (UTC−4) and London on BST (UTC+1), so London is 5 hours ahead: 9:00 AM in New York is 2:00 PM in London, and the two share 3 working hours (9 AM–noon New York time).
Late afternoon in Los Angeles → Tokyo
Los Angeles is on PDT (UTC−7) and Tokyo is UTC+9 all year, 16 hours ahead. 5 PM Tuesday in Los Angeles is 9 AM Wednesday in Tokyo, so their 9-to-5 days never overlap.
London → Mumbai in winter
In December London is on GMT (UTC+0) and India is always UTC+5:30, so 10:00 AM in London is 3:30 PM in Mumbai, leaving 2.5 shared office hours.
Frequently asked questions
What time zone is UTC?+
Coordinated Universal Time (UTC) is the world’s reference time. It does not change for daylight saving. Greenwich Mean Time (GMT) is the same as UTC for everyday purposes; the UK uses GMT in winter and BST (UTC+1) in summer.
How many time zones are there in the world?+
Offsets in use run from UTC−12 to UTC+14. Besides whole-hour offsets there are several half-hour and 45-minute ones, such as India (UTC+5:30), Nepal (UTC+5:45) and Newfoundland (UTC−3:30), giving roughly 38 distinct UTC offsets in total.
Why does the time difference between cities change during the year?+
Countries start and end daylight saving time on different dates, and many never use it. For example, the gap between New York and London shrinks from 5 to 4 hours for two to three weeks in March and for about a week around the end of October.
What is the best time for a call between the US and Europe?+
Late morning on the US East Coast (roughly 9 AM–noon ET) overlaps with the European afternoon. From the US West Coast there is no overlap within both 9-to-5 days; the usual compromise is around 8–9 AM Pacific, which is 4–5 PM in the UK.
Which countries are ahead of everyone else?+
Kiribati’s Line Islands (UTC+14) are the first to see each new day, followed by New Zealand’s Chatham Islands (UTC+13:45 in their summer) and then Samoa, Tonga and New Zealand in summer (UTC+13). American Samoa and Baker Island (UTC−11/−12) are among the last.
Sources