What this calculator does
This tool calculates voltage from a given amount of energy (in joules) and electric charge (in coulombs), the two quantities that define voltage in physics.
How the calculation works
Voltage is defined as energy per unit charge: V = J / C, where J is energy in joules and C is charge in coulombs. This is the actual definition of the volt — one volt equals one joule per coulomb. The calculator divides your entered energy by your entered charge to get the voltage, and returns zero if the charge is zero to avoid an undefined result.
This tool is intended for general physics and electrical engineering education and reference.
Last reviewed August 2026