The flag of Portugal consists of a vertical rectangle with a 2:3 aspect ratio. It is divided into two unequal halves, with the top half being green and the bottom half being red. In the center of the flag is the national coat of arms, which features a shield with a white background, a blue border, and five blue shields with white dots arranged in a cross pattern. Above the shield is a white curved band with the inscription "Ordem e Progresso" (Order and Progress) in black letters.

The precise color codes for the flag's colors are:

• Green: Pantone 354 C / RGB 0 166 79 / HEX #00A64F
• Red: Pantone 186 C / RGB 213 43 30 / HEX #D52B1E

The dimensions of the flag vary depending on its intended use, but the most common measurements are:

• Hoist (width) of the flag: 2 units (for example, 2 meters)
• Fly (length) of the flag: 3 units (for example, 3 meters)
• Diameter of the circular part of the coat of arms: 0.8 units (for example, 80 centimeters)

The geometric properties of the flag include the fact that the division between the green and red halves is not straight, but rather has a small curve near the hoist side. Additionally, the coat of arms is centered both vertically and horizontally within the flag.

It is worth noting that the current design of the Portuguese flag was officially adopted on June 30, 1911, although variations of the flag have been used since the 12th century.