World Clock
A live world clock dashboard with real-time city clocks across global time zones.
This world clock runs entirely in your browser. Nothing is uploaded and no time is sent to any server.
How to use this tool
This world clock dashboard starts running the moment the page loads, showing live city clocks for several major cities at once. To add another location, pick a city from the dropdown and click Add city. Switch between a 12-hour (AM/PM) and a 24-hour display with the format selector. Remove any clock with the small button in its corner, and use Reset to defaults to return to the starting set. Click Copy all times to grab a plain-text snapshot of every clock, which is handy for sharing meeting times across global time zones.
How it works
Your browser knows a single moment in time, the same instant everywhere on Earth. To show international time, the tool takes that one moment from the built-in Date object and asks the browser's Intl.DateTimeFormat API to render it in each city's time zone. The browser already carries an up-to-date time-zone database, so it handles daylight saving time and regional offsets for you. A timer fires once every second to repaint each clock, which keeps the live city clocks accurate down to the second without any network calls.
A real example
Suppose it is 3:00 PM on a Tuesday in New York. New York is on Eastern Time, which is five hours behind UTC during daylight saving, so that same instant is 8:00 PM in London (UTC+1 in summer) and 4:00 AM the next day in Tokyo (UTC+9). The dashboard shows all three side by side: New York reads 3:00 PM Tuesday, London reads 8:00 PM Tuesday, and Tokyo reads 4:00 AM Wednesday. Because the page tracks one shared instant, every clock always agrees about the underlying moment, even when the calendar dates differ.
Common questions
Are the clocks accurate?
They are as accurate as your device's own clock. The tool reads your computer's current time and reformats that single instant for each time zone, so if your system clock is correct, every city clock will be correct too.
Does it handle daylight saving time?
Yes. The conversion uses your browser's built-in time-zone database through the Intl API, which automatically applies daylight saving rules for each region, so the offsets shift correctly during the year.
Do my added cities stay after I refresh?
The dashboard keeps your chosen cities for the current session. Refreshing the page returns it to the default set of major world cities so it always opens ready to use.
Is any of my data sent online?
No. Everything runs locally in your browser using native JavaScript date and formatting features. There are no API calls and nothing about your time or location leaves your device.
Why does a clock show tomorrow's date?
Time zones far ahead of yours, such as Tokyo or Sydney, can already be on the next calendar day. The date shown under each time reflects the local date in that city for the same shared instant.