What can this electrochemistry calculator do?

It covers three common tasks: (1) computing the standard cell potential E°, ΔG°, and the equilibrium constant K from tabulated half-cell potentials; (2) applying the Nernst equation to find E at non-standard concentrations and temperatures; and (3) evaluating simple concentration cells built from the same half-reaction at two different concentrations.

Which sign convention for E and ΔG° does it use?

Following the usual convention, a positive cell potential E (or E°) corresponds to a spontaneous reaction as written, with ΔG° < 0 and an equilibrium constant K greater than 1. If E is negative, the reverse reaction is favored. The tool reports these relationships in the results and in the step-by-step explanation.

Electrochemical cell & Nernst equation calculator

How to use (3 steps)

Choose a mode: standard cell, Nernst equation, or concentration cell.
Enter standard potentials, electron count n, temperature (K), and concentrations or Q as needed.
Compute to see E°, ΔG°, K, E under non-standard conditions, and the calculation log. Copy the URL to share.

A default Zn|Zn²⁺ || Cu²⁺|Cu example is loaded so you can see results immediately. All calculations stay in this browser tab.

Inputs

Pick a mode, adjust the example values, then compute or copy the URL. Units use volts and mol/L for clarity.

Standard cell (E°, ΔG°, K) Nernst equation Concentration cell

Anode half-reaction (label)

Anode E° (V)

Cathode half-reaction (label)

Cathode E° (V)

Electrons n

The standard cell mode assumes standard conditions at 25 °C (about 298 K). For other temperatures or non-standard concentrations, use the Nernst equation or concentration cell modes.

Typically, put the more concentrated solution in C_high and the more dilute solution in C_low. Swapping them will flip the sign of E.

Results

Mode: Standard cell (E°, ΔG°, K)

How it is calculated

Steps will appear here after calculation.

FAQ

Do I need to balance the overall redox equation?

This tool assumes you have already combined and balanced the half-reactions, so the electron count n you enter matches the balanced overall cell reaction. It does not balance redox equations for you, but it does show how E°, ΔG°, K and the Nernst equation relate once n is known.

When should I use the concentration cell mode instead of the general Nernst mode?

Use the concentration cell mode when both half-cells are the same metal/ion pair and only the ion concentration differs. For more complicated cells (different half-reactions on each side), use the general Nernst mode and compute Q from the balanced reaction stoichiometry.

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