Enter the electrode potential and current density into the calculator to determine the Anodic Index.

Anodic Index Formula

The following formula is used to calculate the Anodic Index.

AI = (E - Eref) / I


  • AI is the Anodic Index (V)
  • E is the electrode potential (V)
  • Eref is the reference electrode potential (V)
  • I is the current density (A/m²)

To calculate the Anodic Index, subtract the reference electrode potential from the electrode potential. Then, divide the result by the current density.

What is an Anodic Index?

The Anodic Index, also known as the Electrode Potential, is a measure of the tendency of a metal to corrode or oxidize. It is used in the field of corrosion engineering to predict the compatibility of different metals in contact with each other. A higher Anodic Index indicates a greater likelihood of corrosion. This index is crucial in preventing galvanic corrosion, which occurs when two different metals are in electrical contact in a conductive environment.

How to Calculate Anodic Index?

The following steps outline how to calculate the Anodic Index (AI).

  1. First, determine the electrode potential (E) in volts (V).
  2. Next, determine the reference electrode potential (Eref) in volts (V).
  3. Next, determine the current density (I) in amperes per square meter (A/m²).
  4. Next, gather the formula from above: AI = (E – Eref) / I.
  5. Finally, calculate the Anodic Index (AI).
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Electrode potential (E) = 0.8 V

Reference electrode potential (Eref) = 0.5 V

Current density (I) = 10 A/m²