Electric potential is the potential energy per unit charge associated with a static (time-invariant) electric field, also called the electrostatic potential, typically measured in volts. Metaphorically, electric potential may be conceived of as "electric pressure" that can push electric charges to different locations. Technically, it is the potential φ (a scalar field) associated with the conservative electric field E (E = −∇φ) that occurs when the magnetic field is time invariant (so that ∇ × E = 0 from Faraday's law of induction).

Like any potential function, only the potential difference (voltage) between two points is physically meaningful (neglecting quantum Aharonov-Bohm effects), since any constant can be added to φ without affecting E.

The electric potential is therefore measured in units of energy per unit of electric charge. In SI units, this is:

joules/coulombs = volts.

The electric potential can also be generalized to handle situations with time-varying magnetic fields, in which case the electric field is not conservative and a potential function cannot be defined everywhere in space. There, an effective potential drop is included, associated with the inductance of the circuit. This generalized potential difference is also called the electromotive force (emf).