City comparison · time difference and converter
Seoul is 13 hours ahead of Boston right now. Boston sits in United States on New York; Seoul sits in South Korea on Seoul. They are roughly 10,942 km apart (6,799 mi), a flight of about 13h 52m. Boston's metro holds around 4.9 million people; Seoul's around 25.7 million.
Slot 1
00:00 / 13:00
Boston / Seoul
Partial overlapSlot 2
01:00 / 14:00
Boston / Seoul
Partial overlapSlot 3
02:00 / 15:00
Boston / Seoul
Partial overlapEach row is one hour in Boston. Green rows are inside business hours in both cities; amber means only one side is at their desk; grey rows fall outside business hours in both.
Local Election Day
Seoul, South Korea · 지방 선거일
Wed, Jun 3
Memorial Day
Seoul, South Korea · 현충일
Sat, Jun 6
Juneteenth
Boston, United States
Fri, Jun 19
Great-circle distance
10,942 km
(6,799 mi)
Approximate flight
13h 52m
850 km/h cruise + 1h taxi/climb/descent
Jet lag
13h
Roughly 1 day to adjust per timezone crossed
The heatmap gives you the shape of the day. If you need to convert one specific hour — say a customer call or a release window — open the converter with both cities already loaded.
Open in converter →The difference between Boston and Seoul is not really a number, it's a daily rhythm. Seoul is 13 hours ahead of Boston on the clock today, but the lived version is that Seoul is wrapping up the working day while Boston is still in the morning, and the overlap people actually use is narrow. That gap, more than the raw offset, is what teams have to design around.
In Boston, the working day picks up earliest in the financial districts — Boston's downtown core wakes early and breaks for lunch at the usual hour. The mood in Seoul is its own story: Seoul settles into the evening at the usual hour, with the local commuter pattern setting the pace. If you are scheduling between the two, the heatmap above marks the rows where both patterns line up.
Daylight saving is the other thing to keep an eye on. United States shifts the clock on the second Sunday of March and the first Sunday of November; South Korea either follows its region's DST pattern or stays put all year. When the two changes are weeks apart, the offset between Boston and Seoul is one hour off the usual for that stretch — a cliff that catches recurring calendar invites unless your calendar app rebases them automatically. Pin the meeting to a city, not an offset, and the tool handles the rest.
For travellers, the 13h 52m flight is the short version of the story. The longer one is jet lag: roughly one day of adjustment per timezone crossed, which means a trip across the 13-hour gap costs about 13 groggy days on each side. Pilots and cabin crew swear by morning sunlight and an early walk; whatever your routine, the wall-clock numbers above are the source of truth for your first morning in the new city.