The flag of Thailand consists of five horizontal stripes with the following colors and proportions:

1. Top stripe: Red (#E23D28) - occupies 1/9 of the flag's width
2. Second stripe: White (#FFFFFF) - occupies 1/9 of the flag's width
3. Middle stripe: Blue (#003399) - occupies 2/9 of the flag's width
4. Fourth stripe: White (#FFFFFF) - occupies 1/9 of the flag's width
5. Bottom stripe: Red (#E23D28) - occupies 1/9 of the flag's width

The aspect ratio of the flag is 2:3, meaning its width is two-thirds of its length.