The aspect ratio of Uruguay’s flag is 2:3, meaning its width is two units for every three units of length. This proportion describes the flag’s overall rectangle, not the dimensions of its stripes or canton.
Uruguay’s national flag, officially called the National Pavilion, has nine equal horizontal stripes alternating white and blue. The upper hoist-side corner contains a white canton with the Sun of May. The sun has a face and sixteen alternating rays—eight straight and eight wavy.
The flag was first adopted by law on 18 December 1828, when Uruguay became an independent state after the Cisplatine War. Its original design contained nineteen alternating stripes. A law of 11 July 1830 reduced that number to nine, preserving the symbolism associated with the country’s departments.
The 2:3 ratio is sometimes confused with ratios used by other South American flags, including Argentina’s commonly cited 5:8 proportion. Uruguay also has two other important national banners—the Artigas flag and the flag of the Treinta y Tres—but the 2:3 figure applies to the National Pavilion.