How this calculator works
A volt measures potential difference, while an electronvolt measures energy. The energy gained through an accelerating potential magnitude is charge magnitude times voltage. For a particle carrying z elementary charges, a voltage of V volts gives zV electronvolts. The exact SI elementary charge converts electronvolts to joules. Coulomb-input modes also accept a general charge magnitude without requiring an integer charge number. This is an energy-gain calculation; radiation and other losses are excluded.
Formula
Energy_eV = z V_volts; Energy_J = z e V_volts. 1 eV = 1.602176634e-19 J exactly.
Worked example
A particle with charge magnitude 2e accelerated through 10 V gains 20 eV, or 3.204353268e-18 J. A 3e particle gaining 30 eV requires 10 V.
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Frequently asked questions
Are volts and electronvolts interchangeable?
No. They have different dimensions. The numerical correspondence needs the particle charge.
Does this work for electrons and positive ions?
Yes using charge magnitude and an accelerating orientation of the potential. Both can gain kinetic energy.
Is the relation nonrelativistic?
The energy gained from a potential difference is qV even relativistically. Converting that energy to speed requires the appropriate dynamics.