What is Faraday's constant?

Faraday's constant (F) is 96,485 C/mol, representing the charge of one mole of electrons. It is fundamental to electrolysis calculations.

What is the number of electrons (n) for common ions?

Cu²⁺ uses n = 2, Ag⁺ uses n = 1, Al³⁺ uses n = 3, and H⁺ uses n = 1. This is the ionic charge or valence of the ion being reduced or oxidized.

Can I calculate how long to run electrolysis to deposit a target mass?

Yes. Rearrange the formula: t = (m × n × F) / (M × I). Enter your desired mass, then read the required time from the result panel.

Does this calculator account for efficiency losses?

No. This calculator assumes 100% current efficiency (Faraday's theoretical ideal). Real electroplating systems have current efficiencies of 85–99%, so multiply the theoretical time or current by an efficiency factor for practical use.

What units must I use for correct results?

Current in amperes (A), time in seconds (s), molar mass in grams per mole (g/mol), and n as a dimensionless integer. The output mass is in grams and charge in coulombs.

What is the formula used?

The core formula is m = (M × I × t) / (n × F), derived from Faraday's laws. Charge Q = I × t and moles = Q / (n × F) are intermediate results.

Electrolysis Calculator

Compute mass deposited, moles, or charge in an electrolysis cell using Faraday's first and second laws.

Electrolysis Parameters

Enter current, time, molar mass, and electrons per ion to calculate deposited mass. Target mass is optional and calculates the required time.

Current — I (amperes, A)

Time — t (seconds, s)

Molar Mass — M (g/mol)

Electrons per Ion — n

Target Mass — m (grams, g) (optional: leave blank to compute)

Quick-fill substance

Results

Enter parameters and click Calculate

Faraday's Laws Reference

F = 96,485 C/mol (Faraday's constant)

Q = I × t (charge in coulombs)

m = (M × Q) / (n × F) (mass in grams)

n = number of electrons per ion (valence)

M = molar mass of substance (g/mol)

Summary

This electrolysis calculator applies Faraday's first and second laws of electrolysis to determine how much substance is deposited or dissolved at an electrode. Enter the current, time, molar mass of the substance, and the number of electrons transferred per ion to compute the mass deposited (m), moles (n), and total charge (Q). It is useful for chemistry students, engineers designing electroplating baths, and anyone studying electrochemical processes.

How it works

Enter the current (I) in amperes flowing through the electrolytic cell.
Enter the duration (t) in seconds for which the current flows.
Enter the molar mass (M) of the substance being deposited in g/mol.
Enter the number of electrons (n) transferred per ion (valence/charge number).
The calculator computes charge Q = I × t, moles = Q / (n × F), and mass m = (M × I × t) / (n × F).
Click Calculate or press Enter to view the results.

Use cases

Calculate mass of copper deposited during electroplating.
Determine charge needed to deposit a target mass of silver.
Find moles of hydrogen or oxygen produced during water electrolysis.
Design electroplating baths with precise material yields.
Verify Faraday's law predictions in a school laboratory experiment.
Estimate energy consumption for industrial electrochemical processes.
Convert between charge, time, and mass for electrochemical cells.
Solve electrolysis problems in chemistry and electrochemistry courses.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu