Hanoi
3,359 km²
Seoul
605 km²
Vietnam
South Korea
Area Comparison
Hanoi is 5.6x larger than Seoul
Population Comparison
Hanoi has 1.2x fewer people than Seoul
Hanoi is significantly larger, covering 5.6 times the area of Seoul. Hanoi spans 3,359 km² (1,297 mi²) while Seoul covers 605 km² (234 mi²) — a difference of 2,754 km². You could fit Seoul inside Hanoi approximately 5 times.
To put Hanoi's size in perspective, its area of 3,359 km² is about 1.2x smaller than Rhode Island. Meanwhile, Seoul at 605 km² is about 1.3x smaller than New York City.
Hanoi's footprint is roughly about 470,000 American football fields, 57 times the area of Manhattan, or 32 times the area of Paris — pick whichever unit feels intuitive. Seoul works out to about 85,000 American football fields, 180 times the area of Central Park, or 10 times the area of Manhattan.
Hanoi is the capital and second-most populous municipality of Vietnam. It encompasses an area of 3,358.6 km2 (1,296.8 mi2), and as of 2025 has a population of 8,807,523. Hanoi had the second-highest gross regional domestic product of all Vietnamese provinces and municipalities at US$48 billion in 2023, behind Ho Chi Minh City. It hosts 78 foreign embassies, the headquarters of the Vietnam People's Army (VPA), its Vietnam National University system, and other governmental organizations.
Known as "City Between Rivers", Hanoi covers 3,359 km² with a population of 8.1 million. The city was established in 1010. Hanoi is known for Hoan Kiem Lake, Old Quarter, Temple of Literature, among other attractions. The city's main transit system is the Hanoi Metro.
Hanoi encompasses 3,358.6 square kilometers and had a population of nearly 8.8 million as of 2025.
Seoul, officially Seoul Special Metropolitan City, is the capital and largest city of South Korea, and the largest city in the whole of Korea. The broader Seoul Metropolitan Area, encompassing Seoul, Gyeonggi Province and Incheon, emerged as the world's sixth largest metropolitan economy in 2022, behind New York, Tokyo, Los Angeles, Paris, and London, and hosts more than half of South Korea's population.
Seoul has an area of 605 km² and is home to 9.8 million people. The city dates back to 18 BC. Visitors come for Gyeongbokgung Palace, Gangnam district, Myeongdong shopping, and much more. Getting around is easy with the Seoul Metro.
Seoul Metropolitan Area emerged as the world's sixth largest metropolitan economy in 2022, behind only NYC, Tokyo, LA, Paris, and London.
Looking beyond city limits, the Seoul metropolitan area covers 11,704 km², which is 3.5x larger than greater Hanoi at 3,359 km². The Seoul metro area is also more populous, with 25.5 million people compared to 8.1 million.
Hanoi has a population density of 2,397 people per km² — a moderately dense city. Seoul, with 16,149 people per km², is an extremely dense urban environment. Seoul is dramatically more crowded, with 6.7x the population density.
Both cities are in Asia, but they represent different national approaches to urban development. Hanoi (Vietnam) and Seoul (South Korea) offer a fascinating regional contrast.
Hanoi has a humid subtropical climate while Seoul experiences humid continental conditions. Winters differ dramatically: Hanoi stays around 17°C while Seoul drops to -3°C. When it's noon in Seoul, it's 10:00 AM in Hanoi — a 2-hour time difference.
Size Ratio
Seoul fits inside Hanoi ~5 times
Density Gap
Seoul is 6.7x more densely populated
History
Seoul is ~1,028 years older
Hanoi covers 3,359 km². Cities with a similar urban footprint include Karachi (3,527 km²), Cairo (3,085 km²), Dubai (4,114 km²), Lima (2,672 km²), or Moscow (2,511 km²).
Seoul covers 605 km². Cities with a similar urban footprint include Chicago (606 km²), Madrid (604 km²), Mumbai (603 km²), Toronto (630 km²), or Hyderabad (650 km²).
The straight-line distance from Hanoi to Seoul is 2,742 km (1,704 miles), with an estimated flight time of ~3h 44m.
Want to explore more? Compare city sizes for any two cities worldwide, or share your location live with friends.