How World Clock Works
Every second, the clock asks your browser to format the current instant using each city's IANA time zone name (for example, "Asia/Tokyo"). The browser's built-in time zone database already accounts for UTC offsets and daylight saving rules, so every city shown here stays correct automatically, even across DST changes.
How to Use This Tool
- Scroll the list to see the live time and date in each preset city.
- Type an IANA time zone name — like "Pacific/Auckland" — into the custom field to add any zone that isn't already listed.
- Select Add Time Zone to add it to the live list.
- All times update automatically once a second — no need to refresh the page.
Example
On a January afternoon when it's 3:00 PM in New York (Eastern Standard Time, UTC−5), the list simultaneously shows 8:00 PM in London (UTC+0), 9:00 PM in Paris (Central European Time, UTC+1) and 1:30 AM the next day in Delhi (India Standard Time, UTC+5:30).
Helpful Tips
- Custom zones you add only last for this page visit — add them again next time you need them.
- Time zone names use the format Region/City, such as "Europe/London" or "America/Sao_Paulo" — check the field hint for examples.
- Because each city uses its real IANA zone, daylight saving transitions are reflected automatically without you having to think about it.
Frequently Asked Questions
Why are some cities showing the same time?
Cities in the same time zone, or in zones with the same current UTC offset, will naturally display identical clock times.
What format should I use for a custom time zone?
Use its IANA name, such as "Asia/Singapore" or "Australia/Perth". If the name isn't recognized, the tool will tell you it's invalid.
Does this account for daylight saving time?
Yes. Each zone's offset is resolved live by your browser, so daylight saving changes are applied automatically on the dates they take effect.
Can I remove a preset city?
The preset list is fixed, but you can simply ignore the cities you don't need and focus on the custom zones you've added.
This tool runs entirely in your browser. Your input is not uploaded to any server.