Standard Cell EMF Calculator

About this calculator

The standard cell potential (E°cell) of a galvanic cell is calculated as E°cell = E°cathode − E°anode, subtracting the standard reduction potential of the anode (where oxidation occurs) from that of the cathode (where reduction occurs), both measured in volts against the standard hydrogen electrode. A positive E°cell confirms the reaction is spontaneous as written, which is why, for example, a zinc-copper Daniell cell (Cu²⁺/Cu at +0.34 V, Zn²⁺/Zn at −0.76 V) gives E°cell = +1.10 V.

Chemistry students and electrochemists use this calculation constantly when working through half-reaction tables (as in standard reduction potential references) to predict whether a redox reaction will proceed, to design galvanic or electrolytic cells, and to connect cell potential to Gibbs free energy via ΔG° = −nFE°cell — the sign of E°cell tells you at a glance whether a battery chemistry is viable before any lab work begins.