The flag of Spain has an aspect ratio of 2:3. It consists of three horizontal stripes: the top and bottom stripes are red (#AA151B) and equal in size, while the middle stripe is yellow (#F1BF00) and twice the height of the red stripes. On the left side of the yellow stripe, there is the Spanish coat of arms, which is centered vertically and offset towards the hoist.

The geometric properties and measurements are as follows:

1. The width of each red stripe is 1/4th of the total flag's height.
2. The width of the yellow stripe is 1/2 of the total flag's height.
3. The distance from the hoist to the coat of arms is 1/2 of the red stripe's width.
4. The height of the coat of arms is 2/5 of the yellow stripe's width.