CodeKitHubWhat Is This Tool?
A world clock converter shows what time it is right now in several places at once, using each location's actual IANA time zone rather than a fixed UTC offset. That matters because offsets change with daylight saving time: London is UTC+0 in winter but UTC+1 in summer, and not every country observes daylight saving on the same dates, so a fixed-offset calculation is wrong for roughly half the year in many places.
Beyond just showing 'now', it also converts a specific time you choose — for example, if a meeting is at 3:00 PM in New York, what time is that in Tokyo and Berlin — which is the question people actually have when scheduling across time zones.
Why Use It?
- Uses real time zone data (via the browser's Intl API) so daylight saving time is always handled correctly, unlike calculators that use fixed UTC offsets.
- Compare more than two cities at once, with the time difference between each shown clearly.
- Custom time mode answers 'if it's X here, what time is it there' for scheduling calls and meetings.
- Covers around 50 major cities across every populated continent and time zone.
- Runs entirely in your browser — nothing you enter is sent anywhere.
How to Use
- Select two or more cities from the list to compare their current time.
- Read the time difference shown between each pair of selected cities.
- Switch to custom time mode, enter a specific time in one city, and see the equivalent time in the others.
- Change your selection any time — the times and differences update instantly.
Example
Input
Compare New York and Tokyo on a date in JulyOutput
New York: 9:00 AM (EDT, UTC−4). Tokyo: 10:00 PM (JST, UTC+9). Difference: 13 hoursNew York observes daylight saving time in July (EDT, UTC−4) while Tokyo does not use daylight saving at all (JST, UTC+9 year-round), so the 13-hour gap changes to 14 hours in winter when New York switches to EST (UTC−5).
Common time differences (approximate, varies with DST)
| City A | City B | Typical difference |
|---|---|---|
| New York | London | 5 hours |
| London | Tokyo | 9 hours |
| New York | Tokyo | 13–14 hours |
| Los Angeles | New York | 3 hours |
| Sydney | London | 9–11 hours |
Related tools
For sunrise, sunset and day length at a specific location and date, the sunrise & sunset calculator is a natural companion. If you need to convert a Unix timestamp into a readable date and time, the timestamp converter handles that separately.
Frequently Asked Questions
How do I calculate the time difference between two cities?
Select both cities and the tool subtracts their current UTC offsets automatically, accounting for daylight saving time on both sides. As a manual check: find each city's current UTC offset (for example New York is UTC−4 in summer, Tokyo is UTC+9 year-round), then subtract one offset from the other — the difference here is 13 hours, with Tokyo ahead.
How does daylight saving time (DST) affect the calculation?
Many countries move their clocks forward by one hour in spring and back in autumn, which shifts their UTC offset for part of the year — but not every country does this, and the ones that do switch on different dates. A city like Tokyo or most of China never observes DST, while New York, London and Berlin do but on different calendar dates. Using each city's real time zone identifier (like America/New_York) rather than a fixed offset number is the only way to get this right automatically year-round.
It's 3pm here, what time is it in America?
It depends which part of America — the continental US alone spans four main time zones (Eastern, Central, Mountain, Pacific), roughly four to seven hours behind Central European time depending on the season and the exact city. Pick your city and the specific US city (New York, Chicago, Los Angeles, etc.) to get the exact answer, since 'America' isn't a single time zone.
Why do some cities show the same time but different labels?
Several cities can share the same time zone identifier — for example Paris, Berlin and Madrid are usually all UTC+1 or UTC+2 depending on the season — so their clocks read identically even though they're different cities. Others that look close on a map, like London and Paris, are often one hour apart because they use different time zones.
Is my data stored anywhere?
No. The calculation runs entirely in your browser using the Intl time zone API; nothing you enter or select is sent to a server, stored or logged.