Volts to Electron Volts Calculator - Voltage to eV Energy

The volts to electron volts calculator turns an ordinary voltage reading into energy expressed in electron volts. You enter a voltage in volts and the number of elementary charges (electrons) involved, and the tool returns the energy in electron volts plus its equivalent in joules. This matters because volts describe electric potential, while electron volts describe the energy a single charge gains moving across that potential. The two are linked, not the same unit, and the bridge is the elementary charge. In physics labs and first-year electromagnetism courses, you constantly switch between the volt scale and the eV scale: a 1.5 V battery, a 12 V circuit, or a particle accelerator measured in MeV all rely on the same conversion. Students use this converter to check homework, relate textbook potential-difference problems to energy, and understand why an electron accelerated through one volt gains exactly one electron volt.

• • Homework checks: Verify potential-difference to energy answers without re-deriving the elementary charge each time.
• • Lab voltage readings: Convert a measured voltage into eV and joules for a sensor, particle, or beam carrying n charges.
• • Lecture examples: Show why a single electron across one volt gains exactly one eV in real time during class.
• • Cross-unit sanity checks: Confirm eV and joule outputs agree with the exact 1.602176634 x 10^-19 J per eV constant.

If you already work with electric fields and potential, the link below shows the underlying V = kQ/r field math that produces the voltage you feed here.

Relate this voltage to the underlying V = kQ/r field math with electric potential calculator.

The calculator applies one short rule: energy in electron volts equals voltage times the number of elementary charges. Formally, E_eV = V x n. The intuition is that one electron moving across a 1-volt potential difference gains exactly 1 eV, so a charge of n electrons across V volts stores V x n electron volts. To also show the SI energy, the tool multiplies the eV result by the exact elementary charge constant (1.602176634 x 10^-19 J per eV).

• V: Voltage in volts; the potential difference the charge moves across.
• n: Number of elementary charges (electrons) the energy is computed for.
• e: Elementary charge, exactly 1.602176634 x 10^-19 C, the bridge from volts to eV and joules.

Worked example: convert 5 volts to electron volts for a single elementary charge. V = 5, n = 1, so E_eV = 5 x 1 = 5 eV, which equals 5 x 1.602176634 x 10^-19 = 8.0109 x 10^-19 J. Another example: 12 volts across 2 elementary charges gives 24 eV, or 3.8452 x 10^-18 J. The elementary charge is fixed by the 2019 SI redefinition, so the volt-to-eV bridge does not drift. If the same 12 V acts on a singly charged ion rather than an electron, the energy is still 12 eV, because only the number of elementary charges matters, not the particle's mass. For the formal definition and the exact constant, see the NIST CODATA value of the elementary charge linked below.

According to NIST CODATA 2018, the elementary charge is exactly 1.602176634 x 10^-19 C, which is why 1 eV equals e x 1 V.

See how the same eV unit is used for photon energies at photon energy calculator.

Four ideas make the conversion click. First, the volt is a unit of electric potential difference (joules per coulomb), not energy by itself. Second, the electron volt is a unit of energy: the kinetic energy one electron gains crossing a 1-volt gap. Third, the elementary charge e = 1.602176634 x 10^-19 C is the exact constant that converts between the coulomb and the count of electrons, and therefore between volts and eV. Fourth, 1 eV is exactly 1.602176634 x 10^-19 J by definition. Because the eV is tuned to the electron, it stays the natural unit on atomic scales: a 1.5 V battery does not deliver 1.5 eV to a whole circuit, but a single electron falling through 1.5 V does gain 1.5 eV, which is why device voltages and electron energies are quoted on different but linked scales.

A common point of confusion is whether one volt equals one electron volt: it does not. One volt is a potential; one eV is an energy. They coincide numerically only for a single elementary charge moving across one volt. If you want to see how fast that electron is then moving, the link below converts kinetic energy in eV to velocity.

Convert this kinetic energy in eV into an electron velocity with electron speed calculator.

Follow these steps to convert volts to electron volts, then use the inverse step to check your work.

1. 1 Enter the voltage: Type the voltage in volts (V); use a negative value if your potential difference is reversed.
2. 2 Enter the elementary charges: Type the number of elementary charges (n), usually 1 for a single electron.
3. 3 Read the electron volts: The result is E_eV = V x n, shown as Energy in eV.
4. 4 Read the joules equivalent: The tool multiplies eV by the exact 1.602176634 x 10^-19 J per eV constant.
5. 5 Reverse the step: To go backward, divide eV by n to recover volts (V = E_eV / n).
6. 6 Check edge cases: Voltage 0 or charge count 0 always yields 0 eV, which is a quick sanity check.

Practical example: a cathode-ray tube accelerates electrons through 500 V, so for one electron the energy is 500 eV; for ten electrons it is 5000 eV. This is the same reasoning used when relating voltage to current and resistance, which the Ohm's law calculator linked below works through from the circuit side.

Work through the circuit-side voltage, current, and resistance relationship at Ohm's law calculator.

The volts to electron volts calculator keeps students and technicians from hand-multiplying and rounding the tiny joule constant, and it makes the volt-versus-eV distinction explicit. Keeping both numbers side by side also trains the habit of checking whether a problem expects a potential (volts) or an energy (eV or joules) before plugging values in, which avoids a whole class of unit errors in lab reports.

• • No manual constant: The exact elementary charge is applied for you, so you avoid rounding 1.602176634 x 10^-19 by hand.
• • Both scales at once: A value like 24 eV is immediately visible as 3.845 x 10^-18 J, which helps when a formula expects joules.
• • Prevents unit confusion: It shows volts and eV as different quantities, preventing the classic mistake of treating 1 V and 1 eV as interchangeable.
• • Handles edge inputs: Negative voltages and zero inputs are handled without breaking, which matters when analyzing opposing potentials.
• • Reproducible inverse step: eV to volts is a single division by n, giving a quick check on derivations.
• • Ties to spectroscopy: The eV output feeds directly into wavelength and energy work for atomic transitions.

When you move from energy back to wavelength in spectroscopy, the energy to wavelength calculator linked below takes an eV value and returns the corresponding photon wavelength using the same constant family.

Turn this eV value into the corresponding photon wavelength with energy to wavelength calculator.

Two inputs drive the output: the voltage magnitude and the elementary-charge count. Doubling either doubles the eV result, and the joules figure inherits the same exact constant.

• • The model assumes a single potential step and point charges; it does not track continuous fields, relativistic corrections at very high eV, or a real material's work function.
• • It reports energy, not force or power, so it will not replace a full circuit analysis.

For the inverse direction in pure energy units, the joules to volts calculator linked below converts a joule energy and charge count back to volts using the same elementary charge.

According to BIPM SI Brochure, the electronvolt is defined by the BIPM as the energy gained by one electron passing through a 1-volt potential difference, and 1 eV equals exactly 1.602176634 x 10^-19 J.

Run the inverse eV-to-volts step in pure energy units at joules to volts calculator.