Nernst Equation Calculator

Use this Nernst equation calculator to find cell potential from standard potential, electron count, temperature, and reaction quotient.

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Run the calculator.

Quick Answer: The Nernst equation is E = E0 - (RT / nF) ln Q. At 25 C it is often written as E = E0 - (0.05916 / n) log10 Q.

What This Nernst Equation Calculator Helps You Do

This page keeps the two practical Nernst tasks together: finding cell potential and solving backward for the reaction quotient.

That is enough for most electrochemistry checks without doing logarithm rearrangements by hand.

How to Calculate Nernst Equation Calculator

  1. Choose the target: Solve for cell potential or for the reaction quotient.
  2. Enter E0, n, temperature, and the remaining known value: Temperature is converted to kelvin for the formula.
  3. Apply the Nernst relation: The calculator uses the full logarithmic form of the equation.

Nernst Equation Calculator Formula

E = E0 - (RT / nF) ln Q; Q = exp((E0 - E) nF / RT)
Variable Meaning Unit
E Cell potential under nonstandard conditions V
E0 Standard cell potential V
n Electrons transferred count
Q Reaction quotient dimensionless

Use the worked examples below to check how the formula behaves with real values. If the result looks unexpected, verify the unit assumptions and the meaning of each variable before interpreting the answer.

Worked Examples

Find E - Standard temperature case
  • E0: 1.10 V
  • n: 2
  • Q: 10
  • T: 25 C

Result: E is below E0 because Q is greater than 1.

A larger reaction quotient lowers the cell potential.

Find Q - Potential drop from standard
  • E0: 0.80 V
  • E: 0.74 V
  • n: 1
  • T: 25 C

Result: Q is greater than 1.

A drop below E0 indicates products are favored relative to standard conditions.

How to Interpret Your Results

Range Meaning Action
E close to E0 Reaction conditions are near standard-state behavior. Expect Q near 1.
E much lower than E0 The reaction quotient is large. Product-rich conditions reduce cell potential.

Frequently Asked Questions

It relates electrochemical cell potential to the reaction quotient at a given temperature.

Because the thermodynamic form of the equation uses absolute temperature.

The logarithmic term becomes zero, so E equals E0.
Note: This calculator applies the standard Nernst-equation model and assumes the reaction quotient is dimensionless and defined consistently.

References

Last reviewed: March 2026