The flag of Australia has a blue field (#00008B) with the Union Jack in the canton, and a large white seven-pointed star (the Commonwealth Star) below it. To the right, there is the Southern Cross constellation made up of five white stars.

Aspect ratio: 1:2

Geometric properties:

1. Union Jack: occupies the upper quarter next to the hoist.
2. Commonwealth Star: centered in the lower quarter next to the hoist, diameter 3/5 of the width of the flag.
3. Southern Cross: located on the fly half of the flag, consists of four seven-pointed stars and one smaller five-pointed star.

Measurements:

• Alpha Crucis: 7-pointed star, diameter 1/7 of the flag's width.
• Beta Crucis: 7-pointed star, diameter 1/12 of the flag's width.
• Gamma Crucis: 7-pointed star, diameter 1/12 of the flag's width.
• Delta Crucis: 7-pointed star, diameter 1/14 of the flag's width.
• Epsilon Crucis: 5-pointed star, diameter 1/24 of the flag's width.