What Is the Volt to Electron Volt Calculator?
The electron volt (eV) is a unit of energy equal to the work done moving a single elementary charge through a potential difference of one volt. This calculator converts a voltage (in volts) and a charge number (in elementary charges, e) into energy expressed in electron volts and joules. It is widely used in physics, electronics, and chemistry where particle energies are conveniently described in eV.
How to Use It
Enter the potential difference in volts and the charge in units of the elementary charge. For a single electron or proton, the charge is 1. For a doubly ionized atom it would be 2, and so on. The calculator multiplies the two values to give the energy in eV and also converts that result to joules.
The Formula Explained
The core relationship is $$E\ (\text{eV}) = \text{Voltage (V)} \times \text{Charge (e)}$$ where \(V\) is the voltage and \(Q\) is the charge number in elementary charges. Because 1 eV is by definition the energy gained by one elementary charge crossing 1 volt, a charge number of \(Q\) crossing \(V\) volts gains exactly \(V \times Q\) electron volts. To convert to SI joules, multiply by the elementary charge constant, \(1.602176634 \times 10^{-19}\ \text{J/eV}\).
Worked Example
Suppose an electron (charge number 1) is accelerated through a potential difference of 5,000 volts. The energy gained is $$E = 5000 \times 1 = 5{,}000\ \text{eV}.$$ In joules this is $$5000 \times 1.602176634 \times 10^{-19} = 8.01 \times 10^{-16}\ \text{J}.$$ A doubly charged ion (\(Q = 2\)) through the same voltage would gain 10,000 eV.
FAQ
Is the electron volt a unit of voltage? No. Despite the name, the electron volt is a unit of energy, not voltage. Volts measure potential difference; eV measures energy.
What is the charge number? It is the magnitude of the particle's charge expressed in multiples of the elementary charge e (about \(1.602 \times 10^{-19}\ \text{C}\)). A single electron or proton has a charge number of 1.
How do I convert eV to joules? Multiply the energy in eV by \(1.602176634 \times 10^{-19}\) to get joules.
