In Human Design, Mercury is one of the 13 planetary activations used in the BodyGraph calculation. Mercury's position in the zodiac at the moment of birth (Personality calculation) and at approximately 88 solar degrees before birth (Design calculation) determines which Gate(s) Mercury activates in the BodyGraph. On the Design (Unconscious) side, Mercury governs the Voice — specifically the physical quality, sound, and frequency of the vehicle's voice: how it sounds, what it carries, and how it affects others on an acoustic level. On the Personality (Conscious) side, Mercury governs Communication — the mind's style, content, and approach to expressing itself to others. Mercury is the planet most directly connected to the Throat Center's expression in the BodyGraph.