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Use this calculator to

  • Convert a potential difference into the energy gained by a single electron
  • Work through A-level and undergraduate physics problems on charged particles
  • Express X-ray tube and electron-gun accelerating voltages as particle energies
  • Compare energies for ions carrying more than one elementary charge

Volts to eV Calculator

Convert voltage (V) to electron-volts (eV). 1 eV = 1.60218×10⁻¹⁹ J.

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Formulas

  • eV = V × Q (Q in elementary charge units)

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Common scenarios

Select one to run it in the calculator above.

For business

Why this matters for businesses

Electron-volts sit at the heart of how solar PV cells, battery cells and electrolyser stacks behave. When a procurement team is comparing supplier datasheets for a rooftop PV array or an on-site battery storage system, the cell-level voltage figures translate directly into a single-electron energy figure that determines real-world capacity and efficiency. Getting the conversion right means the panel data, the inverter specification and the modelled annual yield all line up before a £250k capital decision is signed off.

For commercial battery storage, the difference between LFP, NMC and LTO chemistries shows up first in cell voltage. LFP nominal cells sit around 3.2V, NMC closer to 3.7V, LTO around 2.3V. Those numbers translate into the electron-volt energies that drive cycle life, depth of discharge windows and round-trip efficiency claims in supplier proposals. Energy managers benchmarking quotes for a behind-the-meter BESS use this conversion to sense-check whether the headline kWh and cycle-life numbers in a tender response are physically plausible.

Purely Energy works with manufacturers, retailers and commercial property groups evaluating on-site generation and storage as part of a wider procurement strategy. We help finance directors and sustainability leads model the bill impact, the capacity-market implications and the carbon-reporting (SECR) outcome of a PV or BESS investment alongside the supply contract itself. The result is a single, defensible plan that the board can sign off, rather than three separate vendors each quoting a different metric.

Common questions

What is an electron-volt?

An electron-volt (eV) is the energy a single elementary charge gains when it is accelerated through a potential difference of 1 volt. It equals 1.602 x 10^-19 joules. It is a unit of energy, not voltage, and it is the natural scale for atomic and particle physics, where joules are inconveniently large.

How do I convert volts to electron-volts?

Multiply the voltage by the number of elementary charges the particle carries: eV = V x Q. One electron through 12 V gains 12 eV. An alpha particle carries two elementary charges, so the same 12 V gives it 24 eV. For a single electron the numbers match, which is what makes the unit convenient.

Is an electron-volt a measure of voltage?

No, despite the name it measures energy. Volts measure potential difference, the energy available per unit of charge, while electron-volts measure the actual energy a specific charged particle picks up crossing that potential. The conversion between the two needs the particle's charge, which this calculator takes in elementary charge units.

Where are electron-volts used in practice?

Anywhere particle energies are quoted: semiconductor band gaps (silicon is about 1.1 eV), photon energies in spectroscopy, X-ray tube ratings (an electron through a 25 kV tube arrives with 25 keV), and accelerator physics, where energies run to MeV, GeV and TeV. The unit keeps the arithmetic readable at atomic scales.

How many joules is one electron-volt?

1 eV = 1.602 x 10^-19 J, the elementary charge expressed in coulombs multiplied by one volt. Going the other way, one joule is about 6.24 x 10^18 eV. The gulf between the two scales is why eV suits single particles while joules suit everyday electrical engineering.

Related calculators

The conversions that procurement and engineering use alongside this one.

Volts to eV Calculator | Purely Energy