The Golden Ratio is an aesthetic and geometric proportion frequently found in nature, art, and architecture that is most pleasing to the eye. Mathematically, it equals approximately 1.618 (Phi).

It is used in architectural structures (e.g., the Parthenon), famous paintings (e.g., the Mona Lisa), framing in photography, logo designs, and web interface designs to achieve balance.

When a whole is divided into two parts, the ratio of the whole to the larger part equals the ratio of the larger part to the smaller part: (a+b)/a = a/b = 1.618.