The flag of Burundi consists of a white diagonal cross that divides the flag into four sections. The top and bottom sections are red (Pantone 186 C), while the left and right sections are green (Pantone 347 C). There is a white circle in the middle with three six-pointed stars outlined in green (Pantone 347 C) in a triangular formation.

The Pantone color codes are:

• Red: Pantone 186 C
• Green: Pantone 347 C

The aspect ratio of the flag is 3:5, meaning its width is three units and its length is five units. The white diagonal cross has an equal width throughout, amounting to 1/6th of the flag's length. The diameter of the white circle in the center is 2/5ths of the flag's width.

Each of the stars has an outer diameter of 1/4th of the flag's width and an inner diameter of 1/6th of the flag's width. The stars form an equilateral triangle, with each side measuring 2/3rds of the flag's width.

The geometric properties include the equal width of the white cross, the central white circle with a fixed diameter, and the arrangement and dimensions of the three six-pointed stars.