World Clock

Compare local times around the world instantly

Whether you are scheduling a meeting with a colleague in Tokyo, calling a friend in New York, or checking when a live event starts in your timezone, knowing what time it is elsewhere matters. The world clock lets you compare the current local times in multiple cities simultaneously without doing any mental arithmetic. Pick the cities from the dropdowns and the current times appear immediately, updating every second, so you always see a live, accurate comparison rather than a snapshot that goes stale the moment you glance away.

How to use it

Choose a city from each of the three dropdown menus. As soon as you make a selection, that city's clock appears below, ticking in real time alongside the others. There is nothing to submit and nothing to configure beyond picking the places you care about — change any dropdown at any moment and the display updates instantly. The three defaults are set to widely used reference cities, but you can swap any of them for any other city in the list to build the exact comparison you need, whether that is two coasts of the same country or three continents at once.

Why comparing times is harder than it looks

Timezones are not simply a matter of counting hours from a map. Political boundaries, not evenly spaced meridians, decide where one zone ends and another begins, so neighbouring regions can sit hours apart or, in a few cases, share a zone despite being far apart geographically. On top of that, many countries shift their clocks forward or back for daylight saving time, and they do not all do it on the same dates — the Northern and Southern Hemispheres are offset by six months, some countries do not observe it at all, and the exact switch-over dates can differ even between neighbouring countries that do. Add a handful of places that use unusual half-hour or 45-minute offsets from standard time, and manual calculation becomes a genuine source of missed meetings and late calls.

How the clock stays accurate

This tool sidesteps all of that complexity by relying on the timezone database built into your web browser, the same worldwide standard that powers calendars, phones and operating systems. Every city you can select is mapped to its official timezone identifier, and the browser works out the correct current offset for that place at this exact moment, automatically accounting for daylight saving rules and any historical quirks. That means the displayed times are always correct for today's date without you needing to remember whether a particular country is currently observing summer time. The only requirement is that your own device's clock is set correctly, since every comparison is calculated relative to it.

Where a world clock helps

International teams live by this kind of comparison. Scheduling a call across three offices, checking whether a colleague is likely still at their desk, or working out the latest reasonable hour to send a message that needs a same-day reply are all everyday tasks that a quick glance at a world clock solves in seconds. Travellers use it to know when it is safe to call family back home, journalists and traders use it to track market opening hours across financial centres, and fans of live sports or streamed events use it to translate a kick-off or premiere time into their own local hour.

It is equally useful for personal moments — working out whether it is too early or too late to call a relative overseas, planning a video chat with a friend who has moved abroad, or simply satisfying curiosity about what is happening on the other side of the planet right now.

Private, instant and free

There is no sign-up, no cost and no adverts in the way. The whole clock runs as a small piece of code on your own device, reading your system time and applying the browser's built-in timezone rules, so it works instantly and keeps ticking even with no internet connection once the page has loaded. Nothing about which cities you choose is uploaded, logged or shared.

To use it, pick your cities from the three dropdowns and watch the times update live, second by second. Swap any city at any time to compare a different set of places, and rely on the display to handle daylight saving and timezone quirks correctly every time.

A short history of standard time

Before the late nineteenth century, every town effectively kept its own local time based on the sun, which made railway timetables and long-distance communication a genuine headache — two towns just a few dozen kilometres apart could disagree by several minutes. The spread of railways and telegraphs forced the world toward standardised time zones, and an international conference in 1884 established the system of longitude-based zones measured from Greenwich that, with many local adjustments since, still underpins how the world clock on this page works today. Understanding that history explains why zone boundaries follow country borders rather than clean lines of longitude: they were drawn for practical and political convenience, not mathematical neatness. A handful of places even offset by a non-standard 30 or 45 minutes rather than a full hour, a reminder that the whole system, while now globally coordinated, is still a patchwork of national decisions layered on top of an international framework.