The flag of the United Kingdom, also known as the Union Jack or Union Flag, has an aspect ratio of 1:2. It consists of three crosses with specific color codes and measurements:

1. St. George's Cross (England): A red cross (#CC142B) on a white background (#FFFFFF). The width of the red cross is 1/15th the height of the flag.
2. St. Andrew's Cross (Scotland): A diagonal white saltire (#FFFFFF) on a blue background (#012169). The width of the white saltire is 1/30th the height of the flag.
3. St. Patrick's Cross (Ireland): A diagonal red saltire (#CC142B) on a white background (#FFFFFF). The width of the red saltire is 1/30th the height of the flag.

The flag design follows these geometric properties:

• The St. George's Cross divides the flag into four quadrants.
• The St. Andrew's Cross is placed over the St. George's Cross, with the white saltire extending to the corners of the flag.
• The St. Patrick's Cross is placed over the St. Andrew's Cross, with the red saltire extending to the corners of the flag but not touching them.

The intersections of the saltires are counterchanged, meaning the colors alternate in each intersection.