Electroplating Calculator
Calculate plating thickness, deposited metal mass, or plating time using Faraday’s Law of Electrolysis. Pick a metal, enter your current, area and time, or flip the calculator around to find out how long a plating run needs to hit a target thickness.
How to Use the Electroplating Calculator
- Choose your plating metal from the dropdown — copper, nickel, silver, gold, chromium, zinc, tin, cadmium, rhodium, or platinum. The molar mass, valence, density, and a typical current efficiency load automatically, and you can edit any of them if your bath data differs.
- Enter your plating current in amps and the surface area of the part being plated in cm².
- To find out how thick a plate you'll get, switch to "Calculate Thickness" and enter your plating time in minutes.
- To find out how long a run needs to run, switch to "Calculate Time Needed" and enter your target thickness in micrometers instead.
- Click Calculate to see the deposited mass, plating thickness, and time — all based on Faraday's Law of Electrolysis.
What Is an Electroplating Calculator?
An electroplating calculator predicts how much metal will deposit onto a surface during electroplating, based on the current applied, the plating time, the part's surface area, and the properties of the metal being deposited. It's built on Faraday's Law of Electrolysis, a fundamental relationship in electrochemistry that says the amount of metal deposited at an electrode is directly proportional to the amount of electric charge passed through the solution. Instead of running a test plate, measuring it, and adjusting by trial and error, this calculator lets you predict the outcome first, then fine-tune your actual process against the real result.
The Faraday's Law Formula Behind This Calculator
The core equation used here is:
Mass deposited (g) = (I × t × M × η) / (n × F)
Where I is current in amps, t is time in seconds, M is the metal's molar mass in g/mol, η is current efficiency as a fraction, n is the valence (number of electrons transferred per metal ion), and F is Faraday's constant (96,485 coulombs per mole). Once the deposited mass is known, dividing by the metal's density and the plated surface area gives the plating thickness. This calculator runs that same equation in both directions — forward to get thickness from a known time, and backward to get the time needed for a target thickness.
Why Current Efficiency Matters
Not all of the current passed through a plating bath goes toward depositing metal — some of it is lost to side reactions like hydrogen gas evolution at the cathode. This is called current efficiency, or cathode efficiency, and it varies significantly by metal and bath chemistry. Copper and silver baths often run at 95–98% efficiency, meaning almost all the current goes into plating. Hard chromium plating, by contrast, is notoriously inefficient, often running as low as 10–20%, since most of the current is consumed producing hydrogen rather than depositing chromium. This calculator includes typical starting values for each metal, but real bath efficiency depends on your specific formulation, temperature, and agitation, so adjusting this number to match your actual bath's known performance will give far more accurate results.
Typical Electroplating Metal Properties
| Metal | Molar Mass (g/mol) | Valence | Density (g/cm³) | Typical Efficiency |
|---|---|---|---|---|
| Copper (Cu) | 63.55 | 2 | 8.96 | ~98% |
| Nickel (Ni) | 58.69 | 2 | 8.90 | ~95% |
| Silver (Ag) | 107.87 | 1 | 10.49 | ~98% |
| Gold (Au) | 196.97 | 3 | 19.32 | ~95% |
| Chromium (Cr) | 52.00 | 3 | 7.19 | ~15% |
| Zinc (Zn) | 65.38 | 2 | 7.14 | ~90% |
| Tin (Sn) | 118.71 | 2 | 7.28 | ~95% |
| Cadmium (Cd) | 112.41 | 2 | 8.65 | ~90% |
| Rhodium (Rh) | 102.91 | 3 | 12.41 | ~40% |
| Platinum (Pt) | 195.08 | 4 | 21.45 | ~90% |
Frequently Asked Questions
What is Faraday's Law of Electrolysis?
It's the principle that the mass of a substance deposited or released at an electrode during electrolysis is directly proportional to the electric charge passed through the cell, and depends on the substance's molar mass and valence. This calculator applies that law directly to predict plating outcomes.
Why does valence matter in this calculation?
Valence represents how many electrons are needed to deposit one atom of the metal. A metal ion with a higher valence, like Au³⁺ or Cr³⁺, needs more electrons per atom deposited, so it takes more current to plate the same mass compared to a lower-valence ion like Ag⁺.
How accurate is this calculator compared to real plating results?
It's accurate for the theoretical, ideal case defined by Faraday's Law. Real-world results depend heavily on bath temperature, agitation, part geometry, and current distribution, so treat the output as a strong starting estimate and calibrate against an actual test plate for critical work.
What current density should I use for plating?
Current density (current divided by surface area) varies a lot by metal and desired finish quality. This calculator doesn't set a recommended density for you, but you can experiment with different current and area combinations to see how thickness and time change together.
Can I use this for a metal that isn't in the list?
Yes. Select any preset metal, then manually change the molar mass, valence, and density fields to match the metal you're actually plating with.
What is the difference between calculating thickness and calculating time?
Calculate Thickness tells you how thick a plate you'll get from a known current, area, and time. Calculate Time Needed works backward from a target thickness to tell you how long the plating run should last at your given current and area.
Does this calculator account for part geometry or edge effects?
No. It assumes a uniform, simplified surface area and even current distribution. Complex shapes with sharp edges, corners, or recesses often plate unevenly in practice, thicker at edges and thinner in recesses, which this calculator does not model.