You can calculate volts from electron-volts using elementary charge or electron-volts using coulomb.
V to volts calculation with elementary charge
The voltage V in volts (V) is equal to the energy (E) in electron-volts (eV), divided by the electric charge Q in elementary charge or proton/electron charge (e):
V(V) = E(eV) / Q(e)
The elementary charge is the electric charge of 1 electron with the e symbol.
volt = electronvolt / elementary charge
V = eV / e
eV to volts to calculation with coulombs
The voltage V in volts(V) is equal to 1.602176565×10-19 times the energy E in electron-volts (eV), divided by the electrical charge Q in coulombs (C):
V(V) = 1.602176565×10-19 × E(eV) / Q(C)
volt = 1.602176565×10-19 × electronvolt / coulomb
V = 1.602176565×10-19 × eV / C