Volts to eV Calculator

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

How to Use the Volts to eV Calculator

Enter a voltage and a charge in elementary-charge units — the charge field defaults to 1, matching a single electron — and the result is the kinetic energy gained, in electron-volts.

An electron accelerated through a 5-volt potential difference gains exactly 5 eV of kinetic energy. Not approximately — exactly, because that's what an electron-volt is built to describe. Push the same electron through 100 volts and it picks up 100 eV; double the charge (say, an ion missing two electrons instead of one) and the same voltage delivers twice the energy.

Energy (eV) = Voltage (V) × Charge (elementary charge units)

This conversion shows up constantly outside the classroom. Semiconductor band gaps — the energy an electron needs to jump from the valence band to the conduction band — get quoted in eV (silicon's is about 1.1 eV, gallium nitride's around 3.4 eV) because that's the natural scale for the voltages involved at the atomic level. Particle accelerators describe the energy they impart in eV, keV, MeV, and up, for the same reason this calculator exists: energy gained equals accelerating voltage times charge, every time. Spectroscopy leans on the same unit too — a photon's energy in eV translates directly to its wavelength, which is how astronomers and chemists talk about everything from visible light to X-rays on one consistent scale.