Rio de Janeiro
1,221 km²
Buenos Aires
203 km²
Brazil
Argentina
Area Comparison
Rio de Janeiro is 6.0x larger than Buenos Aires
Population Comparison
Rio de Janeiro has 2.2x more people than Buenos Aires
Yes — Rio de Janeiro is 6.0x larger than Buenos Aires by area. Rio de Janeiro spans 1,221 km² (471 mi²) while Buenos Aires covers 203 km² (78 mi²) — a difference of 1,018 km². You could fit Buenos Aires inside Rio de Janeiro approximately 6 times.
To put Rio de Janeiro's size in perspective, its area of 1,221 km² is about 1.3x smaller than London. Meanwhile, Buenos Aires at 203 km² is roughly the same size as Amsterdam.
Rio de Janeiro's footprint is roughly about 171,000 American football fields, 21 times the area of Manhattan, or 12 times the area of Paris — pick whichever unit feels intuitive. Buenos Aires, by comparison, equals about 28,000 American football fields, 100 times the area of Monaco, or 60 times the area of Central Park.
Rio de Janeiro, also known simply as Rio, is the capital of the state of Rio de Janeiro. It is the second-most-populous city in Brazil after São Paulo and the sixth-most-populous city in the Americas.
Known as "Cidade Maravilhosa", Rio de Janeiro covers 1,221 km² with a population of 6.8 million. The city was established in 1565. Rio de Janeiro is known for Christ the Redeemer, Sugarloaf Mountain, Copacabana beach, among other attractions. The city's main transit system is the MetrôRio.
Rio de Janeiro is the second-most-populous city in Brazil after São Paulo and the sixth-most-populous in the Americas.
Buenos Aires, officially the Autonomous City of Buenos Aires, is the capital and largest city of Argentina. It is located on the southwest of the Río de la Plata. Buenos Aires is classified as an Alpha− global city, according to the GaWC 2024 ranking. The city proper has a population of 3.1 million and its urban area has a population of 16.7 million, making it the 21st most populous metropolitan area in the world.
Also known as "Paris of South America", Buenos Aires has an area of 203 km² and is home to 3.1 million people. Its history stretches back to 1536. Visitors come for La Boca's Caminito, Recoleta Cemetery, Teatro Colón, and much more. Getting around is easy with the Buenos Aires Subte.
Buenos Aires is classified as an Alpha− global city according to the GaWC 2024 ranking.
Looking beyond city limits, the Rio de Janeiro metropolitan area covers 6,744 km², which is 1.4x larger than greater Buenos Aires at 4,758 km². The Buenos Aires metro area is also more populous, with 15.2 million people compared to 13.5 million.
Rio de Janeiro has a population density of 5,528 people per km² — a densely populated city. Buenos Aires, with 15,074 people per km², is an extremely dense urban environment. Buenos Aires is noticeably denser, packing 2.7 times more people per square kilometer.
Both cities are in South America, but they represent different national approaches to urban development. Rio de Janeiro (Brazil) and Buenos Aires (Argentina) offer a fascinating regional contrast.
Rio de Janeiro has a tropical savanna climate while Buenos Aires experiences humid subtropical conditions.
Size Ratio
Buenos Aires fits inside Rio de Janeiro ~6 times
Density Gap
Buenos Aires is 2.7x more densely populated
Rio de Janeiro covers 1,221 km². Cities with a similar urban footprint include San Antonio (1,209 km²), Lagos (1,172 km²), Rome (1,285 km²), Los Angeles (1,302 km²), or Hong Kong (1,114 km²).
Buenos Aires covers 203 km². Cities with a similar urban footprint include Helsinki (214 km²), Amsterdam (219 km²), Stockholm (188 km²), Osaka (225 km²), or Boston (232 km²).
The straight-line distance from Rio de Janeiro to Buenos Aires is 1,968 km (1,223 miles), with an estimated flight time of ~2h 49m. See full distance details, including timezone difference and city facts.
Want to explore more? Compare city sizes for any two cities worldwide, or share your location live with friends.