The flag of Thailand, also known as the "Trairanga," has a horizontal five-striped design with the following colors and proportions:

1. Top stripe: Red (#D11231) - 1/6 of the flag's height
2. Second stripe: White (#FFFFFF) - 1/6 of the flag's height
3. Middle stripe: Blue (#0C3F7D) - 2/6 (1/3) of the flag's height
4. Fourth stripe: White (#FFFFFF) - 1/6 of the flag's height
5. Bottom stripe: Red (#D11231) - 1/6 of the flag's height

The flag has an aspect ratio of 2:3, meaning its width is two-thirds of its length. The red, white, and blue stripes are parallel to each other and extend horizontally across the entire length of the flag.