An electronvolt is the amount of energy gained or lost by a single electron when it moves through an electric potential difference of one volt. Hence, it has a value of one volt, which is 1 J/C, multiplied by the elementary charge e = 1.602 176 634 × 10 C. ‍ Therefore, one electronvolt is equal to 1.602 176 634 × 10 J. ‍