The value of an electron volt can be calculated as follows:
E = QU = e * 1 = e = 1.602 * 10^-19 J = 0.1602 aJ.
An electron volt is equal to the electric charge of an electron, or approximately 0.1602 aJ.
It should be noted that an electron volt is not an SI-unit, and thus cannot be used in formulas but has to be converted to joules.
This unit is often used in nuclear and quantum physics.