The flag of Nepal is the world's only non-rectangular national flag. It consists of two triangular shapes, stacked one on top of the other, with a blue border. The upper triangle is crimson red and represents the body of the Hindu god Lord Shiva, while the lower triangle is blue and represents the calmness and peacefulness of Nepal's people.

The aspect ratio of the flag is 5:4, and the height of each triangle is equal to the width of the flag. The blue border around the flag has a width of one-tenth of the total width of the flag. The color codes for the flag are defined by the Nepal Standard Color Codes (NSCC) as follows:

• Crimson Red: NSCC Color No. 135
• Dark Blue: NSCC Color No. 204

The geometric properties of the flag are such that the union jack must be centered in the blue border, and the flag must be flown with the lower triangle under the upper triangle. The exact measurements of the flag depend on its size, but the Ministry of Home Affairs of Nepal recommends a minimum size of five feet by three feet for the national flag.