Question 1

How does the World Clock stay up to date?

Accepted Answer

The World Clock reads your device's clock and re-renders every second, so each city always shows the live current time. All formatting happens locally in your browser using the built-in Intl API — no time data is fetched from a server.

Question 2

How do I add or remove a city or time zone?

Accepted Answer

Open the 'Add a time zone' dropdown and pick any zone from the list. It is populated from your browser's full IANA time zone database (over 400 zones), so you can track virtually any city in the world. Remove a zone at any time with the X button on its card.

Question 3

What is the difference between 12-hour and 24-hour time?

Accepted Answer

24-hour time runs from 00:00 to 23:59 with no AM/PM and is the standard in most of the world. 12-hour time splits the day into AM and PM. Use the toggle to switch every clock between the two formats instantly.

Question 4

Does the World Clock handle daylight saving time (DST)?

Accepted Answer

Yes. Each zone uses its IANA identifier (for example, America/New_York), so daylight saving transitions and each region's current UTC offset are applied automatically by your browser.

Question 5

Is my local time zone detected automatically?

Accepted Answer

Yes. Your device's own time zone is detected and added to the list with a 'Local' badge, alongside a default set of major world cities. You can remove it or add other zones whenever you like.