Nernst Equation Calculator
Calculator
\[ E = E^\circ - \frac{RT}{nF}\ln Q \]
where E, E°, R, T, n, F, and Q denote, respectively, cell potential (V), standard cell potential (V), gas constant (8.314 J·mol⁻¹·K⁻¹), temperature (K), moles of electrons transferred, Faraday's constant (96485 C/mol), and the reaction quotient.
Nernst Equation — Solve For
Result
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E° ↔ Equilibrium Constant K
\[ E^\circ = \frac{RT}{nF}\ln K \]
About This Tool

The Nernst equation describes how the potential of an electrochemical cell depends on the concentrations (or more precisely, the activities) of the species involved. At standard conditions — all species at unit activity, usually 1 mol/L for solutes and 1 atm for gases — the cell potential equals E°. As concentrations deviate from standard, Q changes and the actual potential E shifts accordingly. This calculator solves for any one of the four variables: cell potential E, standard potential E°, reaction quotient Q, or the number of electrons transferred n. Supporting outputs include ΔG = −nFE, the ratio RT/nF, and ln Q. The standard reduction potential reference panel lets you look up common half-reactions and calculate E°cell = E°cathode − E°anode directly. The E° ↔ K converter uses the relation E° = (RT/nF)ln K, linking electrochemistry to thermodynamics and equilibrium.