A planetary mass scale and a system of composition codes are presented for describing the geophysical characteristics of exoplanets and Solar System planets, dwarf planets, and spherical moons. The composition classes characterize the rock, ice, and
gas properties of planetary bodies. The planetary mass scale includes five mass classes with upper and lower mass limits derived from recent studies of the exoplanet mass radius and mass density relationships and the physical characteristics of planets, dwarf planets, and spherical moons in the Solar System. The combined mass and composition codes provide a geophysical classification that allows for comparison of the global mass and composition characteristics of exoplanets with the Solar Systems planets, dwarf planets, and spherical moons. The system is flexible and can be combined with additional codes characterizing other physical, dynamical, or biological characteristics of planets.
