World Clock
See the current local time in cities worldwide at a glance, with time zones, UTC offsets, and day or night.
By Time Tools Editorial Team Last updated
World Clock
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What is a World Clock
A world clock is an online tool that displays the current local time in many cities at the same moment, arranged so you can read every region at a single glance. Instead of calculating offsets in your head or juggling a row of physical clocks on a wall, you see a live, continuously updating panel where each card shows a city, its current time, the calendar date, the time zone abbreviation, and the offset from Coordinated Universal Time. The instant one place ticks past midnight into a new day, the display reflects it, so you always know not just the hour but the date each region is living in.
The purpose of a world clock is coordination. Distributed teams, frequent travelers, and anyone with friends or family abroad need a fast, trustworthy way to answer one question: what time is it there right now? A good world clock removes the guesswork by reading live time zone rules from the IANA Time Zone Database through the browser, which means daylight saving changes are applied automatically for the current date rather than pulled from a stale lookup table that quietly goes out of sync.
This tool starts with a default set of major cities and lets you add the places that matter to you, up to a generous maximum, and remove the ones you no longer need. Each city card also signals whether it is currently day or night, a small touch that makes a big difference when you are deciding whether a message will wake someone or reach them mid-afternoon. If you need to translate one specific meeting time from your zone into another, you can [convert a specific time](/timezone-converter/) with a dedicated converter, then return here to watch the clocks run. Think of the world clock as your always-on dashboard and the converter as the precise calculation for a single scheduled moment.
How It Works
A world clock looks effortless, but a fair amount happens behind each ticking card. When the page loads, the tool reads a list of cities, each mapped to a canonical IANA time zone identifier such as America/New_York, Europe/London, or Asia/Tokyo. For every city, the browser's built-in Intl API is asked to format the current instant in that zone. Because the API knows the full history and current rules of each zone, it returns the correct wall-clock time, the right offset, and the appropriate abbreviation without any manual configuration on your part.
The display then updates on a steady rhythm. Once per second, the tool recomputes the current time for every city so that each displayed value stays within a second of that region's true local time. This is why you can watch the seconds advance in sync across the whole panel. Under the hood there is a single source of truth: the actual current instant, which is identical everywhere on Earth. Each card simply renders that one instant through the lens of its own zone, which is exactly why the times differ while the underlying moment does not.
Adding a city appends a new card and immediately begins updating it on the same one-second tick, and the tool prevents duplicates so the same place cannot appear twice. Removing a city drops its card cleanly from the layout. For each entry, the interface derives the calendar date, the time zone abbreviation, and the UTC offset in a signed hours-and-minutes format, then classifies the local hour as day or night so a quick glance tells you whether a region is awake. If you want to time a specific activity rather than simply read the clocks, you can [run a shared countdown](/countdown-timer/) alongside your dashboard and keep both views visible while you work.
Time Around the World
The times shown on a world clock reflect a patchwork of national decisions rather than a tidy mathematical grid. Some countries occupy a single zone despite spanning great width, while others cross many. Business hours differ too: a nine-to-five workday in one country may be a ten-to-six in another, and afternoon in one capital is the middle of the night in a city just a few cards away. Reading these patterns is the whole point of keeping several clocks side by side.
Daylight saving practices add a moving layer to the picture. North America and much of Europe shift their clocks twice a year, but they do so on different dates, so the gap between, say, New York and London is briefly one hour smaller than usual for a couple of weeks each spring and autumn. Large regions across Asia, Africa, and the equatorial belt do not observe daylight saving time at all, which keeps their offsets fixed year round. A handful of places, such as India and parts of Australia, use offsets that are not whole hours, so rounding to the nearest hour quietly introduces errors.
Because a world clock reads these rules live, you do not have to memorize which cities move their clocks or when. The table below compares several major cities by their standard UTC offset, whether they observe daylight saving time, and their typical business hours, giving you a quick sense of when each place is likely to be reachable. When you want to look further ahead and count the days until a launch or a trip, you can also [measure the gap between two dates](/date-difference-calculator/) and plan around the clocks you are watching here.
| City | UTC Offset | Observes DST | Typical Business Hours |
|---|---|---|---|
| New York, USA | -05:00 | Yes | 9:00 AM to 5:00 PM ET |
| London, UK | +00:00 | Yes | 9:00 AM to 5:30 PM GMT |
| Dubai, UAE | +04:00 | No | 9:00 AM to 6:00 PM GST |
| Mumbai, India | +05:30 | No | 10:00 AM to 6:00 PM IST |
| Tokyo, Japan | +09:00 | No | 9:00 AM to 6:00 PM JST |
| Sydney, Australia | +10:00 | Yes | 9:00 AM to 5:00 PM AEST |
Use Cases
People keep a world clock open for a wide range of reasons, and coordination sits at the center of nearly all of them. Distributed teams are the classic example. When colleagues in San Francisco, London, and Singapore share the same project, a glance at the dashboard shows instantly who is starting their day, who is wrapping up, and who is fast asleep. That awareness shapes when you send a message, when you schedule a live call, and when you simply leave a note for the morning.
Travelers rely on a world clock before and during a trip. Knowing the local time at your destination helps you plan arrivals, book transport, and time calls home so you neither wake anyone at 3 a.m. nor miss them entirely. Many people add their home city and their destination side by side for the length of a journey, then remove the extra card when they return. The day and night indicators make it easy to see at a glance whether it is a reasonable hour to reach someone.
Finance and media audiences watch the clock closely as well. Traders track the open and close of exchanges in New York, London, Tokyo, and Hong Kong, where a few minutes carry real weight. Sports fans, gamers, and viewers of live streams check the host city's time to know when a broadcast begins in their own zone. Families spread across continents use the dashboard to find a window that works for everyone before a group call. And between all that coordinating, if you want to protect a block of deep work, you can [structure focus sessions](/pomodoro-timer/) with a Pomodoro timer while the clocks keep running in the background.
Tips & Common Mistakes
A few habits make a world clock far more useful. First, add only the cities you genuinely track. It is tempting to fill the panel with a dozen places, but a focused set of four to eight is easier to read at a glance and less likely to lead to a misread. Keep your home city on the board as an anchor so every other time has an obvious point of comparison, and remove cards the moment a project or trip ends.
Second, pay attention to the date, not just the clock. When a region is several hours ahead or behind, it is frequently on a different calendar day, so a message you think of as arriving Monday morning may in fact land on the recipient's Tuesday. The date shown on each card exists precisely to prevent that slip. Watch the day and night indicators too, since a time that looks fine numerically may still fall in the middle of someone's night.
Third, remember that daylight saving transitions happen on different dates in different places, and the Southern Hemisphere shifts in the opposite calendar direction from the Northern. During the overlap weeks, the usual gap between two cities can change by an hour, which surprises people who assume the difference is fixed. A common mistake is treating every offset as a whole number of hours; cities such as Mumbai run on a half-hour offset, so eyeballing the difference will be off by thirty minutes. When you need an exact figure for one scheduled moment rather than a live read, [add and subtract time values](/time-calculator/) with a dedicated calculator to avoid the arithmetic slips that catch so many people off guard.
FAQ
How many cities can I display on the world clock at once?
The world clock loads with a default set of major cities and lets you add more up to a maximum of thirty cities shown at the same time. You can remove any city you no longer need, so you can keep the panel focused on just the places that matter to your work, travel, or family.
How accurate are the times shown for each city?
Each city time is computed from the current instant using your browser's built-in Intl API, which reads live rules from the IANA Time Zone Database. The display refreshes once per second, so every city stays within a second of its true local time and daylight saving changes are applied automatically for the current date.
Does the world clock handle daylight saving time automatically?
Yes. Because the tool reads current time zone rules rather than fixed offsets, it applies daylight saving adjustments for each city on the correct dates without any action from you. A city that has just moved its clocks will show the updated offset the next time you view the dashboard.
What does the day or night indicator mean?
Each city card shows whether it is currently daytime or nighttime in that location. Daytime is treated as the hours from 6:00 in the morning through 5:59 in the evening, and every other hour is treated as night. The indicator helps you decide at a glance whether it is a reasonable time to contact someone there.
Why do some cities show an offset like +05:30 instead of a whole hour?
Not every region uses a whole-hour offset from Coordinated Universal Time. India, for example, runs on UTC+05:30, and Nepal uses UTC+05:45. These fractional offsets are deliberate national choices, and the world clock displays them exactly rather than rounding to the nearest hour, so the times you see are precise.
Can I add a city that is already on the dashboard?
No. The world clock prevents duplicates, so if you try to add a city that is already displayed it will decline the addition and let you know the city is already shown. This keeps the panel clean and avoids two identical cards ticking side by side with the same time.
Do I need to install anything or create an account to use it?
No. The world clock runs entirely in your browser, needs no download, and never asks you to sign in. You can open it, add the cities you care about, and start reading times immediately, as often as you like and completely free of charge.