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Time difference between the United States and South Korea

13 hours to 19 hours, depending on the city

Why there is no single answer

The United States spans 6 different offsets in this data — New York at UTC−5, Chicago at UTC−6, Denver at UTC−7, Los Angeles at UTC−8, Anchorage at UTC−9, Honolulu at UTC−10. One number cannot cover 6 offsets, so any single figure for "the United States to South Korea" is a choice of city — declared or not. That is why two sources can both be right and still disagree, and why the useful answer is the table rather than the number.

Every combination

FromToUsual differenceChanges in the year
New YorkSeoul13 hours aheadyes — also 14 hours
ChicagoSeoul14 hours aheadyes — also 15 hours
DenverSeoul15 hours aheadyes — also 16 hours
Los AngelesSeoul16 hours aheadyes — also 17 hours
AnchorageSeoul17 hours aheadyes — also 18 hours
HonoluluSeoul19 hours aheadno

When the gap moves

5 of these 6 combinations change by an hour at some point in the year. New York, Chicago, Denver, Los Angeles and Anchorage go forward on the second Sunday in March and back on the first Sunday in November; Honolulu and Seoul do not change their clocks. Where the two sides change on different weekends, there is a stretch of days when the difference is what neither party expects.

Frequently asked questions

What is the time difference between the United States and South Korea?

There is no single figure. the United States spans 6 of the offsets in this data, so the difference runs from 13 hours (New York to Seoul) to 19 hours (Honolulu to Seoul). Any converter giving one number for this pair has quietly picked a city.

How many hours ahead is South Korea of the United States?

It depends which part of the United States you mean. The table on this page gives every combination; the extremes are 13 hours and 19 hours.

Does the difference between the United States and South Korea change during the year?

Yes. 5 of the 6 city combinations here shift by an hour at some point, because the two sides change their clocks on different weekends or one of them does not change at all.

About these places

New York. New York is UTC−5 in winter and UTC−4 from March to November, and it changes clocks on different weekends from Europe — a fortnight in March and a week in autumn when the transatlantic gap is an hour off what everyone expects.

Chicago. Chicago is UTC−6 in winter, the US Central zone, and the one people most often mean by an unqualified "CST" — a reading that collides with China Standard Time fourteen hours the other way.

Denver. Denver is UTC−7 in winter, the US Mountain zone, and the smallest of the four continental US zones by population. Arizona, in the same zone, does not change its clocks, so for half the year Denver and Phoenix are an hour apart.

Los Angeles. Los Angeles is UTC−8 in winter and UTC−7 from March to November. California voted in 2018 to move to permanent daylight saving and has not been able to: the change needs an act of Congress, which has not come.

Anchorage. Alaska is UTC−9 in winter, one hour behind the US Pacific coast, and covers a longitude range that would justify four zones. The state consolidated into one in 1983 so that Anchorage business hours would overlap with the rest of the country.

Honolulu. Hawaii is UTC−10 and does not change its clocks, so it drifts an hour further from the mainland every March. It is the furthest behind of any populated US zone, and the overlap with a European working day is essentially nil.

Seoul. South Korea is UTC+9, the same as Japan, and briefly used UTC+8:30 in 1954 and again in 1961. North Korea moved to UTC+8:30 in 2015 and back to UTC+9 in 2018 to match the South.

The same pair from the other end

This page reads the difference as South Korea against the United States. South Korea to the United States states the same gap the other way round, which is the one to send someone if they are the one doing the travelling.

Other country pairs

Every the United States pair · All country pairs · City pairs