Electroplating Thickness Calculator
Electroplating uses electrical current to deposit a thin layer of metal onto a substrate. The thickness of the deposited layer is governed by Faraday's law of electrolysis. The thickness equals the mass deposited divided by the product of density and area, where mass = (Q * M) / (n * F). Here Q is the total charge passed (current times time), M is the molar mass of the metal, n is the number of electrons per metal ion, F is the Faraday constant (96,485 C/mol), rho is the density of the metal, and A is the plated area.
Electroplating thickness formula (Faraday's law)
Q = I * t (coulombs) mass = (Q * M) / (n * F) thickness = mass / (rho * A)
F = 96,485 C/mol (Faraday constant). Mass is in grams; thickness in cm, convert to micrometers by multiplying by 10,000. This assumes 100% current efficiency.
Common electroplating metals
- Copper: M = 63.546 g/mol, n = 2, rho = 8.96 g/cm^3.
- Silver: M = 107.868 g/mol, n = 1, rho = 10.49 g/cm^3.
- Nickel: M = 58.693 g/mol, n = 2, rho = 8.91 g/cm^3.
- Gold: M = 196.967 g/mol, n = 3, rho = 19.32 g/cm^3.
- Zinc: M = 65.38 g/mol, n = 2, rho = 7.13 g/cm^3.
Frequently asked questions
What is Faraday's law of electrolysis?
Faraday's first law states that the mass of substance deposited is proportional to the charge passed. Faraday's second law states the mass is inversely proportional to the equivalent weight. Together: mass = (Q * M) / (n * F), where Q is charge, M is molar mass, n is electrons per ion, and F is the Faraday constant (96,485 C/mol).
How do I calculate the charge Q passed?
Q = current (A) * time (s). For example, 2 A for 30 minutes (1,800 s) gives Q = 2 * 1,800 = 3,600 coulombs.
What is the value of n (electrons per ion)?
n is the number of electrons transferred per metal ion during deposition. For copper (Cu2+), n = 2. For silver (Ag+), n = 1. For nickel (Ni2+), n = 2. For gold (Au3+), n = 3.
What are typical electroplating thicknesses?
Decorative gold plating: 0.1 to 0.5 micrometers. Nickel undercoat: 5 to 25 micrometers. Hard chrome: 10 to 500 micrometers. PCB copper: 25 to 35 micrometers (1 mil).
Does the calculation assume 100% current efficiency?
Yes. Real electroplating has current efficiency below 100% because some current produces hydrogen gas instead of depositing metal. Actual thickness = theoretical thickness * current efficiency fraction (e.g., 0.95 for 95% efficiency).
Official sources
- NIST: NIST Faraday constant value.
- IUPAC Gold Book: Faraday's laws of electrolysis.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.