Faraday Converter & Electrolysis Calculator
Convert faraday to coulomb, kilocoulomb, milifaraday, and ampere-hour in one tap — then go further: calculate the mass deposited, the time needed, or the current required with Faraday’s law of electrolysis (m = Q·M / z·F). Built for chemistry students, electroplating workshops, and anyone asking “how many coulombs in a faraday?”. Free, instant, and 100% client-side — no data ever leaves your device.
Faraday to Coulomb Converter
Convert between faraday, coulomb, kilocoulomb, milifaraday, and ampere-hour. 1 faraday = 96,485.33212 C = 26.8015 Ah.
All units at once
| Unit | Value |
|---|
What Is the Faraday Constant?
The Faraday constant (symbol F), named after Michael Faraday, is the magnitude of electric charge carried by one mole of electrons. Its CODATA 2018 value is:
It is not an arbitrary number. The constant is exactly the product of Avogadro’s number (NA = 6.02214076×1023 mol−1) and the elementary charge (e = 1.602176634×10−19 C):
Since the 2019 redefinition of the SI, both NA and e are defined exactly, so the Faraday constant is exact to its stated digits. While most everyday uses of the faraday have been replaced by the SI coulomb, the faraday remains the natural unit of electrochemistry — because chemical equations count moles of electrons, and one faraday is precisely that.
Faraday constant quick facts
| Fact | Value |
|---|---|
| Value (CODATA 2018) | 96,485.33212 C/mol |
| SI unit | coulomb per mole (C/mol) |
| 1 faraday in coulombs | 96,485.33212 C |
| 1 faraday in ampere-hours | 26.8011 Ah |
| 1 coulomb in faradays | 1.0364 × 10−5 F |
| Electrons per faraday | 6.02214076 × 1023 (1 mol) |
| Also equals | 96,485 J/(V·mol) |
Faraday’s Laws of Electrolysis
First law
The mass of a substance deposited or dissolved at an electrode is directly proportional to the quantity of electricity passed: m ∝ Q, where Q = I × t (current in amperes times time in seconds gives coulombs).
Second law
For the same quantity of electricity, the masses deposited from different electrolytes are proportional to their chemical equivalent weights — molar mass divided by z, the number of electrons gained per ion.
The combined formula
where m = mass deposited (g), Q = charge (C), M = molar mass (g/mol), z = electrons per ion, and F = 96,485.33212 C/mol. Rearranged, the same law answers “how long must I plate?” — t = (m × z × F) / (I × M) — and “what current do I need?” — I = (m × z × F) / (t × M).
Worked examples
Example 1 — copper plating: 2 A for 1 hour
Q = 2 × 3,600 = 7,200 C → moles of electrons n = 7,200 / 96,485.33 = 0.07462 mol.
Cu2+ needs z = 2 electrons, M = 63.55 g/mol:
m = 7,200 × 63.55 / (2 × 96,485.33) = 2.371 g of copper.
Example 2 — silver plating: 1.5 A for 45 minutes
Q = 1.5 × 2,700 = 4,050 C. Ag+ needs z = 1 electron, M = 107.87 g/mol:
m = 4,050 × 107.87 / (1 × 96,485.33) = 4.528 g of silver.
Example 3 — how long to plate 10 g of nickel at 3 A?
Ni2+: z = 2, M = 58.69 g/mol.
t = 10 × 2 × 96,485.33 / (3 × 58.69) = 10,959 s ≈ 3 h 2 min 39 s
(at 100% efficiency).
Common Metals Reference Table
Half-reaction data used by the calculator. The last column — grams deposited by exactly one faraday (M/z) — is a handy sanity check for any electroplating calculation.
| Metal | Ion | z (e⁻/ion) | M (g/mol) | g per 1 F |
|---|---|---|---|---|
| Silver | Ag⁺ | 1 | 107.87 | 107.87 |
| Copper | Cu²⁺ | 2 | 63.55 | 31.775 |
| Nickel | Ni²⁺ | 2 | 58.69 | 29.345 |
| Zinc | Zn²⁺ | 2 | 65.38 | 32.69 |
| Gold | Au³⁺ | 3 | 196.97 | 65.657 |
| Chromium | Cr⁶⁺ | 6 | 52.00 | 8.667 |
| Lead | Pb²⁺ | 2 | 207.2 | 103.6 |
| Aluminium | Al³⁺ | 3 | 26.98 | 8.993 |
Values are standard atomic weights rounded for plating calculations; pick “Custom” in the calculator for any other element or oxidation state (e.g. Fe²⁺, Sn⁴⁺).
Frequently Asked Questions
What is the value of the Faraday constant?
The Faraday constant is 96,485.33212 coulombs per mole (C/mol), the CODATA 2018 value. It is the electric charge carried by one mole of electrons, and it is the key constant in every electrolysis calculation.
Why is the Faraday constant 96,485?
Because the Faraday constant equals Avogadro's number times the elementary charge: F = N_A × e = (6.02214076×10^23 mol^-1) × (1.602176634×10^-19 C) = 96,485.33212 C/mol. It is not an arbitrary number — it is the charge of one mole of electrons.
How many coulombs are in one faraday?
One faraday of charge equals 96,485.33212 coulombs. In the other direction, one coulomb equals about 1.0364×10^-5 faradays. Use the converter above for instant faraday to coulomb conversion.
What is the difference between a faraday and a coulomb?
A coulomb is the SI unit of electric charge. A faraday is the charge carried by one mole of electrons — about 96,485 coulombs. Chemists use faradays because they count moles of electrons directly, which is what electrolysis equations need.
What is Faraday's first law of electrolysis?
Faraday's first law states that the mass of a substance deposited or dissolved at an electrode is directly proportional to the quantity of electricity passed through the electrolyte: m ∝ Q, where Q = I × t (current times time).
What is Faraday's second law of electrolysis?
Faraday's second law states that when the same quantity of electricity passes through different electrolytes, the masses deposited are proportional to their chemical equivalent weights (molar mass divided by z, the electrons per ion). Combined with the first law: m = (Q × M) / (z × F).
How do you calculate the mass deposited in electrolysis?
In three steps: (1) charge Q = I × t; (2) moles of electrons n = Q / F; (3) mass m = n × M / z, which combines to m = (Q × M) / (z × F). Example: 2 A for 1 hour through a Cu2+ solution gives Q = 7,200 C and deposits 2.371 g of copper.
How many electrons are in one faraday?
Exactly one mole of electrons: 6.02214076×10^23 electrons (Avogadro's number). That is why the faraday is so useful in chemistry — it converts charge directly into moles.
Why is the actual deposit smaller than the calculated mass?
Current efficiency is rarely 100%. Side reactions, hydrogen or oxygen gas evolution, heating, and cell resistance all consume charge without depositing metal. Industrial electroplating cells typically run at 90–98% efficiency, so multiply the theoretical mass by the efficiency for a realistic estimate.
What is the SI unit of the Faraday constant?
Coulombs per mole (C/mol): charge per mole of electrons. It is sometimes also written as 96,485 J/(V·mol) since one coulomb-volt equals one joule.
Is the Faraday constant exact?
Since the 2019 redefinition of the SI, Avogadro's number and the elementary charge are defined exactly, so the Faraday constant F = N_A × e is exact to its stated digits: 96,485.33212 C/mol.
What is a Faraday bag, and is it related to the Faraday constant?
Not directly. A Faraday bag (or Faraday pouch) is an electromagnetic shielding bag that blocks radio signals to protect phones, key fobs, and cards. It is named after Michael Faraday's work on electromagnetic shielding (the Faraday cage), not after the electrochemical constant — but both honor the same scientist.
Where is Faraday's law used in real life?
Electroplating (chrome, nickel, gold, silver coatings), electrorefining and electrowinning of metals such as copper and aluminium, electroforming, and estimating the charge needed to recharge batteries.
How do I convert faradays to ampere-hours?
One ampere-hour equals 3,600 coulombs, so divide by 3,600: 1 faraday = 96,485.33212 / 3,600 ≈ 26.8015 Ah. For example, a charge of 2 faradays equals about 53.6030 Ah.
Scope boundary
This tool covers: the Faraday constant as a unit of electric charge (faraday ↔ coulomb ↔ kilocoulomb ↔ milifaraday ↔ ampere-hour) and quantitative electrolysis via Faraday’s laws (mass / time / current for plating and refining).
What it does not do: general electric-charge unit conversion across the full SI prefix range, battery energy (mAh ↔ Wh), capacitor charge, or Coulomb’s-law force — those belong to our dedicated electric charge converter.
Related: the charge converter above handles coulomb, millicoulomb, microcoulomb, ampere-hour and more as pure unit conversion; this page is the electrochemistry home of the faraday.