About this tool
Calculate the cell potential of an electrochemical cell under non-standard conditions with the Nernst equation, or rearrange it to solve for the standard potential or the reaction quotient. It also flags whether the reaction is spontaneous. Everything runs in your browser.
The equation used is E = E° − (R × T / (n × F)) × ln(Q), with the gas constant R = 8.314 J/mol·K, the Faraday constant F = 96485 C/mol, n electrons transferred, temperature T in kelvin and reaction quotient Q. At 298.15 K this is equivalent to the familiar E = E° − (0.05916 / n) × log10(Q). The displayed RT/nF term is the slope multiplying ln(Q).
A cell potential greater than zero means the reaction as written is spontaneous (ΔG < 0), while a negative value means it is non-spontaneous and zero indicates equilibrium. Pick what to solve for, enter the known quantities, and the potential, the RT/nF term and the spontaneity note update live.