Hanoi
3,359 km²
San Diego
964 km²
Vietnam
United States
Area Comparison
Hanoi is 3.5x larger than San Diego
Population Comparison
Hanoi has 5.8x more people than San Diego
In terms of area, Hanoi is 3.5x the size of San Diego. Hanoi spans 3,359 km² (1,297 mi²) while San Diego covers 964 km² (372 mi²) — a difference of 2,395 km². You could fit San Diego inside Hanoi approximately 3 times.
To put Hanoi's size in perspective, its area of 3,359 km² is about 1.2x smaller than Rhode Island. Meanwhile, San Diego at 964 km² is roughly the same size as Berlin.
Picture Hanoi another way: its area is large enough to fit about 470,000 American football fields, 57 times the area of Manhattan, or 32 times the area of Paris. San Diego works out to about 135,000 American football fields, 16 times the area of Manhattan, or 9 times the area of Paris.
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.
San Diego is a city on the Pacific coast of Southern California, adjacent to the Mexico–United States border. It is the eighth-most populous city in the U.S. and second-most populous city in California with a population of over 1.4 million, while the San Diego metropolitan area with over 3.3 million residents is the 18th-largest metropolitan area in the country. San Diego is the county seat of San Diego County.
Also known as "America's Finest City", San Diego has an area of 964 km² and is home to 1.4 million people. It was established in 1769. Visitors come for San Diego Zoo, Balboa Park, Coronado Beach, and much more.
San Diego sits directly on the Mexico-United States border, making it California's southwesternmost major city.
Hanoi has a population density of 2,397 people per km² — a moderately dense city. San Diego, with 1,442 people per km², is a relatively spread-out city. Hanoi is noticeably denser, packing 1.7 times more people per square kilometer.
Size Ratio
San Diego fits inside Hanoi ~3 times
Density Gap
Hanoi is 1.7x more densely populated
History
Hanoi is ~759 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).
San Diego covers 964 km². Cities with a similar urban footprint include Abu Dhabi (972 km²), Dallas (997 km²), Berlin (892 km²), Santiago (838 km²), or Hong Kong (1,114 km²).
The straight-line distance from Hanoi to San Diego is 12,494 km (7,763 miles), with an estimated flight time of ~15h 12m.
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