Boston
232 km²
Rio de Janeiro
1,221 km²
USA
Brazil
Area Comparison
Boston is 5.3x smaller than Rio de Janeiro
Population Comparison
Boston has 9.9x fewer people than Rio de Janeiro
In terms of area, Rio de Janeiro is 5.3x the size of Boston. Rio de Janeiro spans 1,221 km² (471 mi²) while Boston covers 232 km² (90 mi²) — a difference of 989 km². You could fit Boston inside Rio de Janeiro approximately 5 times.
To put Boston's size in perspective, its area of 232 km² is roughly the same size as Amsterdam. Meanwhile, Rio de Janeiro at 1,221 km² is about 1.3x smaller than London.
Boston's footprint is roughly about 32,000 American football fields, 110 times the area of Monaco, or 68 times the area of Central Park — pick whichever unit feels intuitive. Rio de Janeiro works out to about 171,000 American football fields, 21 times the area of Manhattan, or 12 times the area of Paris.
Boston is the capital and most populous city of the U.S. state of Massachusetts. It serves as a cultural and financial center of New England, a region of the Northeastern United States. Boston has an area of 48.4 sq mi (125 km2) and a population of 675,647 as of the 2020 census, making it the third-most populous city in the Northeastern United States after New York City and Philadelphia.
Known as "Beantown", Boston covers 232 km² with a population of 0.7 million. The city was established in 1630. Boston is known for Fenway Park, Freedom Trail, Harvard University, among other attractions. The city's main transit system is the MBTA (The T).
Boston covers just 125 km2 yet serves as the cultural and financial heart of all New England
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.
Nicknamed "Cidade Maravilhosa", Rio de Janeiro has an area of 1,221 km² and is home to 6.8 million people. Its history stretches back to 1565. Visitors come for Christ the Redeemer, Sugarloaf Mountain, Copacabana beach, and much more. Getting around is easy with the MetrôRio.
Rio de Janeiro is the second-most-populous city in Brazil after São Paulo and the sixth-most-populous in the Americas.
Looking beyond city limits, the Boston metropolitan area covers 11,700 km², which is 1.7x larger than greater Rio de Janeiro at 6,744 km². The Rio de Janeiro metro area is also more populous, with 13.5 million people compared to 4.9 million.
Boston has a population density of 2,931 people per km² — a moderately dense city. Rio de Janeiro, with 5,528 people per km², is a densely populated city. Rio de Janeiro is noticeably denser, packing 1.9 times more people per square kilometer.
This comparison spans continents — Boston in North America versus Rio de Janeiro in South America. Despite the geographic distance, comparing their sizes reveals surprising insights about how cities grow worldwide.
Boston has a humid continental climate while Rio de Janeiro experiences tropical savanna conditions. Winters differ dramatically: Rio de Janeiro stays around 21°C while Boston drops to -1°C. When it's noon in Rio de Janeiro, it's 10:00 AM in Boston — a 2-hour time difference.
Size Ratio
Boston fits inside Rio de Janeiro ~5 times
Density Gap
Rio de Janeiro is 1.9x more densely populated
Boston covers 232 km². Cities with a similar urban footprint include Osaka (225 km²), Kuala Lumpur (243 km²), Amsterdam (219 km²), Helsinki (214 km²), or Edinburgh (259 km²).
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).
The straight-line distance from Boston to Rio de Janeiro is 7,802 km (4,848 miles), with an estimated flight time of ~9h 41m.
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