World Time Converter
Convert times across time zones.
Time in major world cities
Enter a reference city and time.
What is world time conversion?
Each city has a fixed offset from Coordinated Universal Time (UTC). Converting the reference time to UTC and then applying the target city's offset gives the current time in that city.
The live current time updates every second, down to the seconds. To convert a specific time instead, uncheck “Live current time” and enter the reference city and time manually.
How it is calculated
UTC time = reference time − reference city offset
Target city time = UTC time + target city offset
Major city UTC offset table
| City | UTC offset |
|---|---|
| Seoul | UTC+9 |
| Tokyo | UTC+9 |
| Beijing | UTC+8 |
| New York | UTC−5 |
| Los Angeles | UTC−8 |
| London | UTC+0 |
| Paris | UTC+1 |
| Dubai | UTC+4 |
| Sydney | UTC+11 |
Why time differences exist — the principle behind UTC offsets
Earth completes one full rotation (360°) every 24 hours, so sunrise and sunset shift by one hour for every 15° of longitude (360 ÷ 24). To manage this in practice, the world is divided into time zones, each expressed as a UTC offset — the number of hours it sits ahead of or behind Coordinated Universal Time (UTC).
Korea uses UTC+9, meaning it is 9 hours ahead of UTC — when it's 00:00 UTC, it's already 09:00 in Seoul. This calculator converts the reference city's local time to UTC, then adds the target city's offset, converting world time in two steps.
Countries that use daylight saving time, and why Korea abolished it
Many countries at higher latitudes, including the US and much of Europe, observe daylight saving time (DST) each year, moving clocks forward by an hour to make better use of longer summer daylight — typically springing forward in spring and falling back in autumn.
Korea has its own history with DST: it was introduced and repealed several times from the late 1940s through the 1960s, and reinstated around 1987–1988 ahead of the Seoul Olympics. Ongoing confusion and questionable benefits eventually led to its full abolition, and Korea now uses a fixed UTC+9 standard time year-round. This is also why this calculator relies only on fixed UTC offsets without DST adjustments.
Scheduling an overseas video call — Seoul and New York
Seoul (UTC+9) and New York (UTC−5, standard time) differ by 9 − (−5) = 14 hours, with Seoul ahead. A 9:00 AM meeting in Seoul falls at 9:00 minus 14 hours in New York — 7:00 PM the previous day — well outside a typical New York workday (roughly 9 AM to 6 PM).
A time that works for both sides is closer to Seoul's evening (around 9–10 PM), which lines up with New York's morning (around 7–8 AM). Note that New York observes daylight saving time from roughly March to November, shifting to UTC−4, so the actual local time can differ from this calculator's result by up to an hour — always confirm the final time with your counterpart.