City comparison · time difference and converter
Sydney is 1 hour ahead of Seoul right now. Seoul sits in South Korea on Seoul; Sydney sits in Australia on Sydney. They are roughly 8,329 km apart (5,175 mi), a flight of about 10h 48m. Seoul's metro holds around 25.7 million people; Sydney's around 5.3 million.
Slot 1
09:00 / 10:00
Seoul / Sydney
Both inside business hoursSlot 2
10:00 / 11:00
Seoul / Sydney
Both inside business hoursSlot 3
11:00 / 12:00
Seoul / Sydney
Both inside business hoursEach row is one hour in Seoul. 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
Great-circle distance
8,329 km
(5,175 mi)
Approximate flight
10h 48m
850 km/h cruise + 1h taxi/climb/descent
Jet lag
1h
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 Seoul and Sydney is not really a number, it's a daily rhythm. Sydney is 1 hour ahead of Seoul on the clock today, but the lived version is that Sydney is wrapping up the working day while Seoul 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 Seoul, the working day picks up earliest in the financial districts — Seoul's downtown core wakes early and breaks for lunch at the usual hour. The mood in Sydney is its own story: Sydney's harbourside offices empty by 17:30 with Friday drinks at the Rocks. 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. South Korea either observes DST or holds a fixed offset year-round; Australia either follows its region's DST pattern or stays put all year. When the two changes are weeks apart, the offset between Seoul and Sydney 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 10h 48m 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 1-hour gap costs about 1 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.