Coulombs to Moles Calculator

Calculator Inputs

Use direct charge for known coulombs, or switch to current and time when charge must be derived first.

Input mode

Charge (C)

Current (A)

Time value

Time unit

Current efficiency (%)

Electrons per mole product

Faraday constant (C/mol)

Target moles of product

Product or ion label

Formula used

Direct charge mode: n(e−) = Qeff / F

Current-time mode: Q = I × t

Efficiency correction: Qeff = Q × (η / 100)

Product moles: n(product) = n(e−) / z

Target charge estimate: Qrequired = target × z × F / (η / 100)

Here, Q is applied charge in coulombs, Qeff is efficiency-adjusted charge, F is the Faraday constant, η is current efficiency, and z is electrons required per mole of product.

How to use this calculator

Select whether you already know the charge or need it from current and time.
Enter charge directly, or provide current, time value, and a time unit.
Set current efficiency to account for side reactions or practical losses.
Enter the electron stoichiometry for one mole of your product.
Keep the Faraday constant default unless your workflow requires another value.
Optionally add a target mole value to estimate required applied charge.
Click calculate to view the result summary, steps, graph, and export buttons.

Example data table

Applied charge (C)	Efficiency (%)	Electrons per mole	Moles of electrons	Moles of product
48,242.67	100	1	0.5000	0.5000
96,485.33	95	2	0.9500	0.4750
192,970.66	90	3	1.8000	0.6000
289,455.99	85	4	2.5500	0.6375

FAQs

1) What does this calculator convert?

It converts electrical charge into moles of electrons, then into moles of product or ions using electron stoichiometry. It also handles efficiency losses and current-time charge generation.

2) Why is the Faraday constant important?

The Faraday constant links charge to chemical amount. One mole of electrons carries about 96,485 coulombs, so dividing effective charge by this value gives electron moles.

3) What does electrons per mole product mean?

It is the number of electrons needed to form one mole of your chosen product. For example, Cu²⁺ to Cu needs two electrons per mole of copper.

4) When should I use current and time mode?

Use it when charge is not given directly. The calculator first computes charge from current multiplied by time, then applies efficiency and stoichiometry.

5) Why does efficiency reduce the result?

Not every coulomb drives the target reaction. Side reactions, heat, and practical losses lower the useful charge, so product moles decrease when efficiency is below 100%.

6) Can I estimate charge needed for a target yield?

Yes. Enter target moles and the calculator estimates the applied charge needed after accounting for electron stoichiometry and efficiency losses.

7) Does the sign of charge matter here?

This page uses the magnitude of charge for mole conversion. In electrochemistry, direction still matters for reaction type, but the mole calculation uses charge amount.

8) Should I report electrons or product moles?

Report electron moles for charge-transfer analysis. Report product moles when you need chemical yield, deposition amount, or stoichiometric reaction output.