eV to Volts Calculator

Enter an energy in electron-volts and a charge to calculate the equivalent voltage.

How to Use the eV to Volts Calculator

Enter an energy in electron-volts and a charge in elementary-charge units — charge defaults to 1, for a single electron or proton — and the voltage comes out immediately.

This isn't an empirical formula with a fudge factor or a measured constant baked in; it's a straight definition. One electron-volt is, by definition, the kinetic energy a single elementary charge gains crossing a one-volt potential difference. Divide any energy in eV by the number of elementary charges involved, and what's left is the voltage that would produce exactly that energy gain.

Volts = Energy (eV) ÷ Charge (elementary charge units)

Worth sitting with for a second: the electron-volt isn't really a unit of voltage at all, despite the name suggesting otherwise — it's a unit of energy, sized specifically around this relationship so physicists don't have to keep converting back and forth between joules and volts every time they talk about a particle's kinetic energy. That's also why particle physicists describe collision energies in GeV or TeV rather than in volts — a proton in the Large Hadron Collider gains 13 TeV of energy, not "13 trillion volts," because energy is the quantity that actually matters for what happens when particles collide.

Set charge to anything other than 1 and the tool answers a slightly different question: what average potential difference would move a charge of that size through a given total energy — useful for multiply-ionized particles (charge 2, 3, and so on) rather than single electrons.