Osaka
225 km²
Rio de Janeiro
1,221 km²
Japan
Brazil
Area Comparison
Osaka is 5.4x smaller than Rio de Janeiro
Population Comparison
Osaka has 2.5x fewer people than Rio de Janeiro
In terms of area, Rio de Janeiro is 5.4x the size of Osaka. Rio de Janeiro spans 1,221 km² (471 mi²) while Osaka covers 225 km² (87 mi²) — a difference of 996 km². You could fit Osaka inside Rio de Janeiro approximately 5 times.
To put Osaka's size in perspective, its area of 225 km² is roughly the same size as Amsterdam. Meanwhile, Rio de Janeiro at 1,221 km² is about 1.3x smaller than London.
In more relatable units, Osaka's 225 km² is about 32,000 American football fields, 110 times the area of Monaco, or 66 times the area of Central Park. For Rio de Janeiro, that's about 171,000 American football fields, 21 times the area of Manhattan, or 12 times the area of Paris.
Osaka is a designated city in the Kansai region of Honshu in Japan. It is the capital of and most populous city in Osaka Prefecture, and the third-most populous city in Japan, following the special wards of Tokyo and Yokohama. With an estimated population of 2,816,247 as of October 1, 2025 and a population density of about 12,505 people per square kilometer, it is the largest component of the Keihanshin Metropolitan Area, the second-largest metropolitan area in Japan and the 10th-largest urban…
Known as "Nation's Kitchen", Osaka covers 225 km² with a population of 2.8 million. The city was established in 645. Osaka is known for Osaka Castle, Dotonbori district, Universal Studios Japan, among other attractions. The city's main transit system is the Osaka Metro.
Osaka is the third-most populous city in Japan, following the special wards of Tokyo and Yokohama.
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. The city dates 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 Osaka metropolitan area covers 13,228 km², which is 2.0x larger than greater Rio de Janeiro at 6,744 km². The Osaka metro area is also more populous, with 19.3 million people compared to 13.5 million.
Osaka has a population density of 12,222 people per km² — an extremely dense urban environment. Rio de Janeiro, with 5,528 people per km², is a densely populated city. Osaka is noticeably denser, packing 2.2 times more people per square kilometer.
This comparison spans continents — Osaka in Asia versus Rio de Janeiro in South America. Despite the geographic distance, comparing their sizes reveals surprising insights about how cities grow worldwide.
Osaka has a humid subtropical climate while Rio de Janeiro experiences tropical savanna conditions. Winters differ dramatically: Rio de Janeiro stays around 21°C while Osaka drops to 5°C. When it's noon in Osaka, it's midnight in Rio de Janeiro — a 12-hour time difference.
Size Ratio
Osaka fits inside Rio de Janeiro ~5 times
Density Gap
Osaka is 2.2x more densely populated
Time Difference
12 hours apart
History
Osaka is ~920 years older
Osaka covers 225 km². Cities with a similar urban footprint include Amsterdam (219 km²), Boston (232 km²), Helsinki (214 km²), Kuala Lumpur (243 km²), or Buenos Aires (203 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 Osaka to Rio de Janeiro is 18,698 km (11,618 miles), with an estimated flight time of ~22h 30m.
Want to explore more? Compare city sizes for any two cities worldwide, or share your location live with friends.