World Clock
Display current time across multiple time zones simultaneously. Add any time zone from 80+ cities worldwide.
World Clock
What is a World Clock?
A world clock shows the current time in several places at once. Instead of converting one time zone at a time, it lays the cities out as side-by-side cards so you can compare them at a glance. That makes it easy to see whether a colleague on the other side of the world is starting their day, finishing it, or fast asleep.
This tool reads the time from your device and converts it with the browser's built-in Intl.DateTimeFormat API, which draws on the IANA time zone database. Because that database carries the full rule for every zone, daylight-saving changes are applied automatically — there is no need to add or subtract an hour by hand when a region shifts its clocks.
Sixteen major zones are loaded by default, from UTC and the four continental United States zones to London, Paris, Berlin, Moscow, Dubai, Kolkata, Singapore, Tokyo, Shanghai, Sydney, and Auckland. You can add more from a list of over eighty cities, remove any card with its close button, switch every clock between 24-hour and 12-hour display, or restore the defaults at any time.
Each card shows the live time, the weekday and date, the region, and the offset from UTC that is currently in force for that city. The offset is worked out by comparing the zone's local time with UTC at the moment you view it, so it always reflects whatever rule — standard or daylight saving — is active right now.
Key Features of This Clock
- Eighty-plus time zones — every continent is represented, from Honolulu to Auckland.
- Sixteen defaults — a sensible set of major cities appears the moment the page loads.
- Live updates — all clocks refresh once every second.
- Current UTC offset — each card reports the offset actually in effect, including daylight saving.
- 12-hour and 24-hour modes — one button switches the whole grid.
- Instant reset — one click restores the standard set of time zones.
- Add time zones — Open the dropdown, pick a city, and click + Add. The new card appears in the grid and starts ticking immediately.
- Read each card — Every card shows the live time, the weekday and date, the region, and the current UTC offset for that city.
- Toggle 12h or 24h — Press the format button to switch every clock between 24-hour and 12-hour display.
- Remove a city — Click the x in the corner of a card to drop that time zone from the grid.
- Restore the defaults — Click Reset Defaults to bring back the standard set of sixteen major world time zones.
UTC Offset Reference
The default time zones use the IANA identifiers shown below. Where two offsets are listed, the larger one applies during daylight saving; the card always displays whichever value is currently in force at the city.
| City | IANA time zone | Typical UTC offset |
|---|---|---|
| UTC | UTC | UTC+00:00 |
| New York | America/New_York | UTC−05:00 / −04:00 |
| Chicago | America/Chicago | UTC−06:00 / −05:00 |
| Denver | America/Denver | UTC−07:00 / −06:00 |
| Los Angeles | America/Los_Angeles | UTC−08:00 / −07:00 |
| London | Europe/London | UTC+00:00 / +01:00 |
| Paris | Europe/Paris | UTC+01:00 / +02:00 |
| Berlin | Europe/Berlin | UTC+01:00 / +02:00 |
| Moscow | Europe/Moscow | UTC+03:00 |
| Dubai | Asia/Dubai | UTC+04:00 |
| Kolkata | Asia/Kolkata | UTC+05:30 |
| Singapore | Asia/Singapore | UTC+08:00 |
| Shanghai | Asia/Shanghai | UTC+08:00 |
| Tokyo | Asia/Tokyo | UTC+09:00 |
| Sydney | Australia/Sydney | UTC+10:00 / +11:00 |
| Auckland | Pacific/Auckland | UTC+12:00 / +13:00 |
Worked Examples
- London to Tokyo — when it is 12:00 in London (UTC+00:00 in winter), Tokyo (UTC+09:00) reads 21:00 the same day.
- London to New York — New York is five hours behind London in winter, so 15:00 in London is 10:00 in New York.
- Berlin to Tokyo — a 09:00 meeting in Berlin (UTC+01:00 in winter) lands at 17:00 in Tokyo (UTC+09:00).
- Los Angeles to Sydney — with Los Angeles at UTC−08:00 and Sydney at UTC+11:00, 10:00 in Los Angeles is 05:00 the next day in Sydney.
- Half-hour offsets — India runs on UTC+05:30, so when UTC is 12:00, Kolkata reads 17:30.
- Quarter-hour offsets — Kathmandu uses UTC+05:45, so the same 12:00 UTC becomes 17:45 there.
Tips and Common Mistakes
- Offsets are not fixed — many cities shift by an hour twice a year, so never memorise a single number; read the offset shown on the card.
- Days can differ — a city on the far side of the Pacific may already be on tomorrow's date, or still on yesterday's.
- Duplicates are ignored — adding a time zone you already display has no effect; each city appears only once.
- Selections are not saved — reloading the page brings back the sixteen default zones, so re-add your cities each visit.
- 24-hour is the default — press the format button to switch every clock to 12-hour time with AM and PM.
- Your device clock is the source — if the system time on your computer is wrong, every card is wrong, so keep automatic time enabled.
Common Use Cases
A world clock is most valuable whenever you deal with people or events in more than one region. These are the situations it is built for.
- Remote and distributed teams — see who is likely online before sending a message or booking a call.
- Scheduling international meetings — line up a single slot that falls inside working hours for every attendee.
- Financial markets — track the opening and closing bells of exchanges in New York, London, and Tokyo.
- Family and friends abroad — check whether it is a reasonable hour before calling someone overseas.
- Travel planning — work out arrival times and jet-lag before you fly.
- Global broadcasts and events — convert a single start time into the local time of every audience you care about.
Are the times updated in real time?
Yes. The clocks update every second to show the current time for each selected time zone, and each card also refreshes its weekday, date, and UTC offset. You can leave the page open and the display will keep ticking without any manual refresh.
Does this account for Daylight Saving Time (DST)?
Yes. The clock uses the browser's built-in time zone database through the Intl.DateTimeFormat API, which applies the daylight-saving rules for each region automatically. When a country shifts its clocks, both the displayed time and the UTC offset on that card update on their own.
What time zones are available?
Over 80 time zones covering major cities across North America, South America, Europe, Asia, Africa, Australia, and the Pacific Islands. Sixteen of them load by default, and you can add any of the rest from the dropdown at any time.
Can I save my custom time zone selection?
No. Selections are not persisted between page loads, so reloading the page restores the standard set of sixteen default zones. You can re-add your preferred cities in seconds, and bookmarks give you a quick way to return to the tool.
Why do some cities show a half-hour or quarter-hour offset?
Not every region sits on a whole-hour offset. India is UTC+05:30 and Nepal, shown here as Kathmandu, is UTC+05:45, so their clocks run half or three-quarters of an hour out. The tool reports the exact offset rather than rounding it.
Why is the date on some clocks different from mine?
A time zone on the far side of the world can be a full calendar day ahead of you or still a day behind. When it is late evening in London, for example, it is already the next morning in Tokyo, so the two cards show different dates as well as different times.
Does the world clock work offline?
Once the page has loaded, yes. All of the time zone data and the ticking logic live in the browser, so the clocks keep running without a connection. Only the initial page load needs network access.
Can I change the order of the clocks?
Clocks are laid out in the order you add them. If you remove a city and add it again it moves to the end of the grid. Pressing Reset Defaults restores both the original sixteen zones and their standard order.