Cell Potential Calculator: Electrochemical Voltage

What is Cell Potential?

Cell potential (E°_cell) is the voltage generated by an electrochemical cell at standard conditions. It drives electrons from the anode (oxidation) through an external circuit to the cathode (reduction). Understanding cell potential is essential for designing batteries, fuel cells, and electrolytic processes.

⚡ Cell Potential Calculator

Use our free calculator for instant, accurate results.

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📐 Formula

E°_cell = E°_cathode − E°_anode

Values from Standard Reduction Potential table (vs. Standard Hydrogen Electrode, SHE). Positive E°_cell = spontaneous reaction.

📝 Worked Example

Zinc-Copper (Daniell) cell:
Cu²⁺/Cu: E° = +0.34V (cathode)
Zn²⁺/Zn: E° = −0.76V (anode)
E°_cell = 0.34 − (−0.76) = +1.10V ✓ spontaneous

📝 How to Use the Calculator

Select Cathode Half-ReactionChoose the reduction half-reaction (higher reduction potential).

Select Anode Half-ReactionChoose the oxidation half-reaction (lower reduction potential; flipped).

Calculate E°_cellView standard cell potential and determine spontaneity.

Apply Nernst EquationAdjust for non-standard concentrations using E = E° − (RT/nF)lnQ.

❓ FAQ

What does a negative cell potential mean?

A negative E°_cell indicates a non-spontaneous reaction under standard conditions. Energy input is required — as in electrolysis (ΔG = −nFE, positive ΔG when E is negative).

What is the Nernst equation?

E = E° − (0.0592/n)×logQ at 25°C. It adjusts cell voltage for actual concentrations, not just standard 1M solutions.

What is Cell Potential?