Electrolysis Calculator
The mass deposited or gas evolved in electrolysis — from current, time and the number of electrons per ion.
Faraday's laws: charge is current × time, and one mole of electrons carries 96,485 coulombs.
How the electrolysis calculator works
Faraday's laws: charge is current × time, and one mole of electrons carries 96,485 coulombs. So moles deposited = It/(nF), and mass follows from the molar mass.
Electroplating and metal refining are sized directly from this. It also gives the time: depositing a gram of copper at one amp takes about 50 minutes, which is why industrial plating runs at hundreds of amps.
Formula: m = M I t / (n F)
Worked examples
| Inputs | Mass deposited | Note |
|---|---|---|
| 2 A for 60 minutes onto copper | 2.37099 g | 2.37 g |
| Silver instead | 8.04941 g | 8.05 g — one electron, heavier atom |
| At 90% efficiency | 2.13389 g | 10% less |
FAQFrequently asked questions
What are Faraday's laws?
The mass deposited is proportional to the charge passed, and inversely proportional to the electrons each ion needs.
What is Faraday's constant?
96,485 coulombs per mole of electrons — the charge on one mole of electrons.
How long to plate one gram of copper?
About 25 minutes at 2 A, or 50 at 1 A.
What is current efficiency?
The share of current that does the wanted reaction. The rest usually goes into hydrogen evolution — real plating baths run 90 to 98%.
Why do aluminium smelters use so much power?
Because aluminium needs three electrons per atom and is light, so each kilogram takes about 10.7 million coulombs — plus a high cell voltage. Smelters run at hundreds of thousands of amps.
Where these figures come from
- IUPAC — Standard atomic weights (2021 conventional values) — the molar-mass table
- NIST — CODATA 2018 fundamental physical constants — Avogadro constant, gas constant, speed of light
- NIST Chemistry WebBook — thermochemical data
- CSIRO — Australia's national science agency
Last checked: September 2026. Atomic masses are the IUPAC conventional values; constants are CODATA 2018; equations are the standard textbook forms.