San Francisco
121 km²
Seoul
605 km²
USA
South Korea
Area Comparison
San Francisco is 5.0x smaller than Seoul
Population Comparison
San Francisco has 11.2x fewer people than Seoul
Seoul is significantly larger, covering 5.0 times the area of San Francisco. Seoul spans 605 km² (234 mi²) while San Francisco covers 121 km² (47 mi²) — a difference of 484 km². You could fit San Francisco inside Seoul approximately 5 times.
To put San Francisco's size in perspective, its area of 121 km² is about 1.2x the size of Paris (city proper). Meanwhile, Seoul at 605 km² is about 1.3x smaller than New York City.
San Francisco's footprint is roughly about 17,000 American football fields, 60 times the area of Monaco, or 35 times the area of Central Park — pick whichever unit feels intuitive. Seoul, by comparison, equals about 85,000 American football fields, 180 times the area of Central Park, or 10 times the area of Manhattan.
San Francisco, officially the City and County of San Francisco, is the fourth-most populous city in California and the 17th-most populous in the United States, with a population of 826,079 in 2025. Among U.S. cities with a population of 300,000 or more, San Francisco is ranked first by per capita income, second by population density, and sixth by aggregate income as of 2023.
Known as "The City by the Bay", San Francisco covers 121 km² with a population of 0.9 million. The city was established in 1776. San Francisco is known for Golden Gate Bridge, Alcatraz Island, Cable cars, among other attractions. The city's main transit system is the BART & Muni.
San Francisco ranks first by per capita income among all US cities with 300,000+ residents as of 2023.
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 1.7x larger than greater San Francisco at 6,984 km². The Seoul metro area is also more populous, with 25.5 million people compared to 4.7 million.
San Francisco has a population density of 7,190 people per km² — a densely populated city. Seoul, with 16,149 people per km², is an extremely dense urban environment. Seoul is noticeably denser, packing 2.2 times more people per square kilometer.
This comparison spans continents — San Francisco in North America versus Seoul in Asia. Despite the geographic distance, comparing their sizes reveals surprising insights about how cities grow worldwide.
San Francisco has a Mediterranean climate while Seoul experiences humid continental conditions. When it's noon in Seoul, it's midnight in San Francisco — a 17-hour time difference.
Size Ratio
San Francisco fits inside Seoul ~5 times
Density Gap
Seoul is 2.2x more densely populated
Time Difference
17 hours apart
History
Seoul is ~1,794 years older
San Francisco covers 121 km². Cities with a similar urban footprint include Vancouver (115 km²), Paris (105 km²), Miami (143 km²), Barcelona (101 km²), or Lisbon (100 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 San Francisco to Seoul is 9,029 km (5,610 miles), with an estimated flight time of ~11h 7m.
Want to explore more? Compare city sizes for any two cities worldwide, or share your location live with friends.