What unit is used to measure voltage?

Voltage is measured in volts, which is the standard unit for electrical potential difference in the International System of Units (SI). The volt quantifies the potential energy per unit charge that drives the flow of electric current in a circuit. When a voltage is applied across two points in a circuit, it causes electrons to move, resulting in electrical current.

To understand the context of the other options: amps, or amperes, measure the rate of flow of electric charge (current), ohms measure the resistance within a circuit, and joules are units of energy. Each of these units plays a critical role in electrical engineering, but for measuring voltage specifically, volts are the appropriate unit.