World clock
Add the cities you care about to see their time at a glance, ticking every second. Each clock shows the date, the UTC offset, how far ahead or behind you it is, and whether it is day or night there.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- The page starts with seven well-known zones. Press the × on a clock to remove it.
- To add another, type the zone name (a list of suggestions appears) and press Add. Up to twelve clocks fit.
- Look at the line under each time: it shows the date, whether it is day, evening or night, the UTC offset and how many hours the place is ahead of or behind you.
How it works
Each clock asks the browser’s built-in time zone database for the local time and the UTC offset at the current moment, once per second. The clocks only run while the tab is visible; when you return, they catch up at once, so a hidden tab does not use any power for the clocks.
Worked example
When it is 12:00 in London in winter, it is 07:00 in New York (UTC−5), 17:30 in Kolkata (UTC+5:30), 21:00 in Tokyo (UTC+9) and 23:00 in Sydney (UTC+11, summer time). New York and Tokyo are 14 hours apart, so a call at 07:00 in New York is at 21:00 in Tokyo.
Tips
- To plan a meeting at a given time, use the time zone converter, which turns one time into the others.
- Zone names with a region, such as America/Argentina/Buenos_Aires, are shown by the city part only.
Frequently asked questions
How do I add a city?
Type its time zone in the box, for example America/Chicago or Asia/Dubai, and press Add. The list of suggestions offers every zone your browser knows. Zones are named after a big city in the region.
Are my clocks saved?
Yes, in your browser on this device, so they are still there next time. Nothing is sent to a server. You can remove clocks one by one, or reset the list to the default cities.
How are day and night decided?
By the local clock: from 06:00 to 17:59 is day, 18:00 to 21:59 is evening, and the rest is night. It is a quick guide, not the real sunrise; for that, use the sunrise and sunset calculator.
Does it handle daylight saving time?
Yes. The offsets come from the time zone database in your browser, so they change on the right days in each region. The offset shown next to a clock is the one in force now.