Electrolysis Calculator

Use this electrolysis calculator to estimate deposited mass from current and time, or solve the required current for a target electrolysis yield.

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Run the calculator.

Quick Answer: Faraday's law gives m = MIt / (nF), where M is molar mass, I is current, t is time, n is electrons transferred, and F is Faraday's constant.

What This Electrolysis Calculator Helps You Do

This page gives you the two most useful Faraday-law workflows: find the mass produced from an applied current, or solve the current needed to reach a target mass in a fixed time. That covers the typical lab, homework, and plating-style questions without extra bookkeeping.

The result also reports total charge passed so you can check whether the answer matches the physical scale of the electrolysis setup.

How to Calculate Electrolysis Calculator

  1. Choose the target quantity: Use mass mode when current and time are known, or current mode when you need the amperage required for a target mass.
  2. Enter electrochemical inputs: Supply molar mass, electron count, current or mass target, and the electrolysis time in minutes.
  3. Apply Faraday's law: The calculator converts minutes to seconds, computes total charge, and then solves the Faraday-law relationship.
  4. Interpret the practical result: Higher current or longer time increases the deposited mass, while larger electron counts reduce mass gained per coulomb.

Electrolysis Calculator Formula

m = MIt / (nF); rearranged for current: I = mnF / (Mt)
Variable Meaning Unit
m Mass deposited or liberated g
M Molar mass of the species g/mol
I Current A
t Electrolysis time s or min
n Electrons transferred per mole count

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

Mass mode - Copper deposition
  • Current: 2.0 A
  • Time: 30 min
  • Molar mass: 63.55 g/mol
  • Electrons: 2

Result: Deposited mass is about 1.19 g.

Copper plating increases with charge passed through the cell.

Mass mode - Silver deposition
  • Current: 0.50 A
  • Time: 20 min
  • Molar mass: 107.87 g/mol
  • Electrons: 1

Result: Deposited mass is about 0.67 g.

A one-electron process deposits more mass per coulomb than a two-electron process of similar molar mass.

Current mode - Target aluminum mass
  • Target mass: 1.00 g
  • Time: 60 min
  • Molar mass: 26.98 g/mol
  • Electrons: 3

Result: Required current is about 4.97 A.

The lower molar mass and three-electron transfer demand more current to reach the target mass in one hour.

Water electrolysis style - Hydrogen target estimate
  • Target mass: 0.10 g
  • Time: 15 min
  • Molar mass: 2.016 g/mol
  • Electrons: 2

Result: Current requirement is high because the target mass represents many moles of hydrogen gas.

Gas-evolution problems often require substantial charge despite a small target mass.

How to Interpret Your Results

Range Meaning Action
Low current or short time Small charge passed through the cell. Expect only a small amount of deposited or liberated substance.
Moderate charge Useful production or plating scale for many lab examples. Check whether the assumed efficiency matches the real setup.
High current demand The target mass is ambitious for the chosen time. Increase electrolysis time or reconsider process efficiency and heat limits.

Frequently Asked Questions

It states that the mass deposited or liberated at an electrode is proportional to the electric charge that passes through the cell.

Use m = MIt / (nF) with consistent units for molar mass, current, time, and electron count.

It is the mass deposited per unit charge and equals M / (nF) for the species being electrolyzed.

Because n tells you how many moles of electrons are required per mole of substance transformed at the electrode.
Note: This calculator assumes 100% current efficiency. Real cells may produce less product because of side reactions, resistance, or incomplete collection.

References

Last reviewed: March 2026