Cell Potential Calculator

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Calculate the standard electromotive force (EMF) of an electrochemical cell.

Reduction Potentials

Cathode Potential (E° cathode)

Anode Potential (E° anode)

Calculation Results

Enter standard reduction potentials to calculate the cell potential

About this calculator

Overview

Cell potential (E°cell) represents the electromotive force of an electrochemical cell, measuring the driving force for electron transfer between anode and cathode. It determines whether a redox reaction will occur spontaneously (positive potential) or requires external energy (negative potential). The potential depends on the difference between the reduction potentials of the two half-reactions, with the more positive reduction potential determining the cathode.

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Pro Tips

Always identify the cathode (reduction, more positive E°) and anode (oxidation, more negative E°) correctly - the cell potential is E°cathode - E°anode.
Standard reduction potentials are measured at 25°C, 1 atm pressure, and 1 M concentrations - real cell potentials vary with conditions.
For non-standard conditions, use the Nernst equation: E = E° - (RT/nF)ln(Q), where Q is the reaction quotient.
When combining half-reactions, the cell potential equals the reduction potential of the cathode minus the reduction potential of the anode.
Galvanic cells (positive E°) produce electricity spontaneously, while electrolytic cells (negative E°) require external power.
The maximum work obtainable from a cell is w_max = -nFE°cell, relating electrical potential directly to Gibbs free energy change.
Always double-check your half-reactions - the electrons must balance, and the cell potential calculation assumes standard conditions.

Fun Facts

"The Daniell cell, invented in 1836, was the first practical battery with a stable voltage of 1.10V, revolutionizing telegraph networks and establishing the foundation of modern electrochemistry."
"A positive cell potential indicates spontaneous reaction, but the actual voltage delivered depends on conditions - concentration, temperature, and current draw all affect the working potential."
"The standard hydrogen electrode (SHE) defines 0.00 V as the reference point for all reduction potentials, using the reaction 2H⁺ + 2e⁻ ⇌ H₂ at standard conditions."
"Lead-acid batteries, invented in 1859, were the first rechargeable batteries and still power most vehicles today, with a cell potential of about 2.1V."
"Lithium-ion batteries achieve high energy density through lithium's extremely negative reduction potential (-3.04 V), enabling compact, long-lasting power for electronics."
"The highest cell potentials come from fluorine-based systems (up to 6V), but practical batteries balance voltage with stability and safety considerations."
"Fuel cells like the hydrogen-oxygen system can theoretically achieve 1.23V, but real systems operate at lower voltages due to kinetic limitations."
"Temperature affects cell potential - most cells increase voltage slightly with heating, but extreme temperatures can cause thermal runaway in batteries."

Formula: E°cell = E°cathode - E°anode