Learn how to calculate potential difference step-by-step with this comprehensive guide. Understand the concepts, formulas, and applications.. Electric Potential Difference Formula Vxy= Vx - Vy = [Wx - Wy]/q SI Unit of Electrical Potential Difference The SI Unit of Electrical potential difference is the same as the electric potential, i.e, Voltage or Volts. Note: Why a unit charge is taken to explain the concept of Electric Potential? A small unit charge will have very small electric field which will neither affect not distort the field produced by the bigger charge and hence, the concept can be explained easily. Difference Between ... Learn what potential difference (voltage) means in simple terms. Understand its definition, formula, unit (volt), and how it's measured using a voltmeter with easy examples. Electric potential (also called the electric field potential, potential drop, the electrostatic potential) is the difference in electric potential energy per unit of electric charge between two points in a static electric field.