The coulomb, abbreviated C, is the SI unit of electric charge. One coulomb is defined as the amount of charge transported by a current of one ampere in one second, so 1 C equals 1 A·s. A single electron carries a charge of about 1.602 × 10^-19 coulombs, which means one coulomb represents approximately 6.24 × 10^18 electrons. In practical battery terms, a 1000 mAh battery stores about 3600 coulombs of charge at its rated capacity.

Electric Charge Converter

Q: What is the difference between voltage and electric charge?

Voltage, measured in volts, is electrical potential difference, meaning the pressure that drives current through a circuit. Electric charge, measured in coulombs, is the quantity of electricity, meaning the total amount of electrons that have moved. They are related through current: current in amperes is charge in coulombs flowing per second. A battery's voltage describes the force it can deliver, while its ampere-hour rating describes the total charge it stores. This converter handles electric charge units, not voltage units.

Q: How do I convert milliampere-hours (mAh) to coulombs?

One milliampere-hour equals 3.6 coulombs. To convert mAh to coulombs, multiply by 3.6. For example, a 4500 mAh battery equals 4500 × 3.6 = 16200 coulombs. To convert in the other direction, divide by 3.6. Because the converter lists ampere-hours rather than milliampere-hours, you can divide the mAh value by 1000 first to convert it to Ah, or multiply the Ah result by 1000 afterward to return to mAh.

Q: What is the Faraday unit of charge?

The Faraday, abbreviated Fd, is a unit of electric charge equal to the charge carried by one mole of electrons, which is approximately 96485 coulombs. It is used mainly in electrochemistry to relate the amount of electricity passed during electrolysis to the amount of chemical change produced. It is named after Michael Faraday. It should not be confused with the farad, abbreviated F, which is the SI unit of capacitance.

Q: What are abcoulombs and stat coulombs?

Abcoulombs and stat coulombs are electric charge units from the older CGS system of units, which predates the SI system used today. The abcoulomb comes from the electromagnetic CGS subsystem and equals 10 coulombs. The stat coulomb, also called the franklin, comes from the electrostatic CGS subsystem and equals about 3.336 × 10^-10 coulombs. These units appear mainly in older physics literature and specialized scientific references. For modern work, it is best to convert them to coulombs first.

Q: What is the relationship between ampere-hours and coulombs?

One ampere-hour equals exactly 3600 coulombs. This follows directly from the definition of current: one ampere is one coulomb per second, so one ampere flowing for one hour, which is 3600 seconds, transfers 3600 coulombs of charge. Ampere-hours are commonly used for battery capacity because they describe how long a battery can deliver a given current, while coulombs are the SI unit more often used in physics and engineering calculations.

Q: Can I use this tool to compare battery capacities?

Yes. To compare battery capacities, convert them to the same unit such as coulombs or ampere-hours first. For example, a battery rated at 10 Ah equals 36000 coulombs, while a battery rated at 8000 mAh equals 8 Ah or 28800 coulombs, so the 10 Ah battery has greater capacity. If a battery is rated in kilowatt-hours, which is an energy unit rather than a charge unit, you also need the voltage to convert it into ampere-hours or coulombs.

Convert voltage units instantly—millivolts (mV), volts (V), kilovolts (kV) and more. Enter a value, choose units, and get accurate conversions in seconds. Useful for electronics, engineering, education, and technical documentation. Free, fast, and easy to use.

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Electric Charge Converter

The Electric Charge Converter converts between eight units of electric charge: the coulomb (SI unit), ampere-hour (practical battery capacity unit), four units from the Faraday electrochemistry system, and two legacy CGS units (abcoulomb and stat coulomb). Select the source and target units, enter the value, and click Convert.

Electric charge is the fundamental quantity that describes how much electricity has passed through a circuit, how much capacity a battery holds, or how much material an electrolysis process can deposit. Understanding which unit is used in a given context — and converting between them accurately — is essential for battery engineering, electrochemistry, and physics calculations.

This tool converts electric charge units — coulombs, ampere-hours, faradays, and CGS charge units. It does not convert voltage units (volts, millivolts, kilovolts). Voltage (measured in volts) and electric charge (measured in coulombs) are different physical quantities. If you are looking to convert mV to V or V to kV, those conversions are simple powers of 10: 1 V = 1,000 mV; 1 kV = 1,000 V — no tool is needed for SI prefix conversion.

How to use the Electric Charge Converter

Enter the charge value to convert.
Select the From unit — the unit your value is currently in (e.g. coulombs, ampere-hours, faradays).
Select the To unit — the unit you want to convert to.
Click Convert. The result is displayed immediately.
To convert the same value to additional units, change the To dropdown and click Convert again.

All 8 units — conversion factors and contexts

The table below shows every supported unit, its value in coulombs (the SI standard), and the context in which it is typically used:

Unit	In coulombs (C)	Typical context
SI unit
Coulomb (C)	1 C	The SI base unit of electric charge. Defined as the charge transported by a current of one ampere in one second (1 C = 1 A·s). Used in all modern physics and electrical engineering calculations.
Practical unit
Ampere-hour (A·h)	3,600 C	Battery and capacitor capacity rating. A battery rated at 2,000 mAh (milliampere-hours) = 2 Ah = 7,200 C. Used universally on consumer batteries, EV battery packs, and UPS systems. 1 A·h = charge delivered by 1 amp flowing for 1 hour = 3,600 coulombs.
Electrochemistry units (Faraday system)
Faraday (Fd)	96,485 C	The charge carried by one mole of electrons (or one mole of singly charged ions). Named after Michael Faraday. 1 Faraday = 96,485.3321 C (approximately 96,485 C). Used in electrochemistry for electrolysis calculations, electrode reactions, and electroplating. Distinct from the farad (F), which is the SI unit of capacitance.
Milli faraday (mFd)	96.485 C	One thousandth of a Faraday (one millimole of electron charge). Used in electrochemical calculations involving small quantities of charge transfer, particularly in analytical chemistry and laboratory-scale electrolysis.
Micro faraday (uFd)	0.096485 C	One millionth of a Faraday (one micromole of electron charge). Used in electrochemical measurements at very small scales, such as thin-film deposition, microelectrode experiments, and trace electroanalysis.
Pico faraday (pFd)	9.6485e-11 C	One trillionth of a Faraday. Used in highly precise electrochemical measurements. Important: do not confuse with picofarad (pF), which is a unit of capacitance (10^-12 farads). These are entirely different physical quantities.
CGS units (legacy physics)
Abcoulomb (abC)	10 C	The electromagnetic CGS unit of electric charge. 1 abcoulomb = 10 coulombs exactly. Part of the older Gaussian/CGS-EMU system used in physics before SI was standardized. Encountered in older physics literature and some specialized electromagnetic texts.
Stat coulomb (statC)	3.336e-10 C	The electrostatic CGS unit of electric charge (also called franklin or esu of charge). 1 stat coulomb = 3.33564 x 10^-10 coulombs. Part of the CGS-ESU (electrostatic unit) system. Found in electrostatics literature, Gaussian units used in theoretical physics, and older scientific papers.

Faraday (charge) vs farad (capacitance) — a critical distinction

The Faraday and the farad are completely different physical quantities that share a name origin (both honor Michael Faraday) but measure entirely different things. The Faraday (Fd) is a unit of electric charge: approximately 96,485 coulombs — the charge carried by one mole of electrons. It is used in electrochemistry. The farad (F) is the SI unit of electrical capacitance: how much charge a capacitor stores per volt of applied potential. Similarly, picofarad (pF) and microfarad (uF) as capacitance units are ubiquitous in electronics — every capacitor is rated in farads or its submultiples. Pico faraday (pFd) and micro faraday (uFd) as fractions of the Faraday charge unit are only encountered in specialized electrochemistry. When you see 'pF' on a capacitor datasheet, it means picofarad (capacitance). In this converter, pFd means Pico faraday (charge). Do not confuse them.

Electric charge — what it is and why it matters

What is electric charge?

Electric charge is a fundamental property of matter measured in coulombs (C). Current (measured in amperes, A) is the rate of charge flow: 1 ampere = 1 coulomb per second. This relationship — Q = I x t (charge equals current multiplied by time) — connects the coulomb to the practical ampere-hour unit used for batteries: 1 A flowing for 1 hour = 3,600 C = 1 A·h.

Battery capacity in ampere-hours

Ampere-hours (A·h) — or milliampere-hours (mAh) for smaller batteries — measure how much total charge a battery can deliver. A 3,000 mAh smartphone battery can deliver 3,000 milliamps for one hour, or 1,500 mA for two hours, or 300 mA for ten hours. In coulombs: 3,000 mAh = 3 Ah = 3 x 3,600 = 10,800 C. Converting between A·h and coulombs is the most common practical use of this converter.

The Faraday in electrochemistry

Faraday's first law of electrolysis states that the mass of a substance deposited at an electrode is proportional to the total charge passed. The Faraday constant (approximately 96,485 C/mol) represents the charge carried by one mole of electrons. To deposit one mole of a monovalent metal (like silver, Ag), exactly one Faraday of charge must pass. For divalent metals (like copper, Cu²⁺), two Faradays are required per mole. The Faraday unit enables direct calculation of how much charge is needed for a specific quantity of electrochemical reaction.

Common use cases

Scenario	Common conversion	Notes
Battery capacity — comparing or calculating runtime	A·h to C (or mAh to C)	Smartphone batteries are typically rated in mAh (milliampere-hours). 1 mAh = 3.6 C. A 4,500 mAh battery = 4.5 Ah = 16,200 C. To estimate runtime: battery capacity (Ah) divided by device current draw (A) = hours of use.
Electrolysis and electroplating calculations	C to Faraday (or A·h to Faraday)	Faraday's laws of electrolysis: mass deposited = (M x Q) / (n x F), where M = molar mass, Q = charge in coulombs, n = valence, F = Faraday constant (96,485 C). Convert total charge passed (in C or A·h) to Faradays to find moles of material deposited or dissolved.
EV and large battery pack capacity	kWh to A·h (requires voltage)	EV batteries are often rated in kWh (energy) rather than Ah (charge). Converting requires the pack voltage: Ah = Wh / V. A 75 kWh pack at 400 V nominal = 75,000 / 400 = 187.5 Ah. This converter handles charge units; energy-to-charge conversion requires the voltage value.
Capacitor charge calculations	C to coulombs directly	The charge stored in a capacitor: Q = C x V (capacitance in farads multiplied by voltage in volts). A 100 uF capacitor at 12 V stores Q = 100 x 10^-6 x 12 = 0.0012 C = 1.2 mC. For charge unit conversions in this context, the coulomb is the natural unit.
Physics and chemistry coursework	Various to coulombs	Convert all charge values to coulombs for consistent SI calculations. CGS units (abcoulombs, stat coulombs) and the Faraday unit appear in older textbooks and some specialized literature. The converter handles all eight units, so you can translate any unit encountered in source material to coulombs for calculation.

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Frequently asked questions

What is the difference between voltage and electric charge?

Voltage (measured in volts, V) is electrical potential difference — the 'pressure' that drives electric current through a circuit. Electric charge (measured in coulombs, C) is the quantity of electricity — the total amount of electrons that have moved. They are related through current: current (amperes) is charge (coulombs) flowing per unit time (seconds). A battery's voltage describes the force it delivers; its ampere-hour rating describes the total charge it stores. This converter handles electric charge units, not voltage units.

What is a coulomb?

The coulomb (C) is the SI unit of electric charge. One coulomb is defined as the charge transported by a current of one ampere in one second (1 C = 1 A·s). A single electron carries a charge of approximately 1.602 x 10^-19 coulombs — so one coulomb represents approximately 6.24 x 10^18 electrons. In everyday terms, a 1,000 mAh battery contains approximately 3,600 coulombs of charge at its rated capacity.

How do I convert milliampere-hours (mAh) to coulombs?

1 milliampere-hour = 3.6 coulombs. To convert mAh to C: multiply by 3.6. Example: a 4,500 mAh battery = 4,500 x 3.6 = 16,200 C. To convert in the other direction (C to mAh): divide by 3.6. The Ampere-hour unit in the converter corresponds to A·h (not mAh); to use it for mAh values, enter the mAh figure divided by 1,000 (to get A·h) or multiply the result by 1,000 to convert A·h back to mAh.

What is the Faraday unit of charge?

The Faraday (Fd) is a unit of electric charge equal to the charge carried by one mole of electrons: approximately 96,485 coulombs. It is used primarily in electrochemistry to relate the amount of electricity passed during electrolysis to the quantity of chemical change produced. It is named after Michael Faraday. Do not confuse it with the farad (F), which is the SI unit of electrical capacitance — the two units are entirely different physical quantities despite sharing a name origin.

What are abcoulombs and stat coulombs?

Abcoulombs and stat coulombs are charge units from the older CGS (centimeter-gram-second) system of units, which predates the SI system now used internationally. The abcoulomb (abC) comes from the electromagnetic CGS subsystem: 1 abC = 10 coulombs. The stat coulomb (statC, also called the franklin) comes from the electrostatic CGS subsystem: 1 statC = approximately 3.336 x 10^-10 coulombs. Both appear in older physics literature and some specialized scientific papers. For any modern calculation, convert to coulombs first.

What is the relationship between ampere-hours and coulombs?

1 ampere-hour (A·h) = 3,600 coulombs exactly. This follows from the definition: 1 ampere = 1 coulomb per second, so 1 A flowing for 1 hour (3,600 seconds) = 3,600 C. Ampere-hours are the practical unit for battery capacity because they directly answer 'how long can this battery power a given device'. Coulombs are the SI unit used in physics calculations and formulae. Both measure the same physical quantity — total electric charge — just in different units.

Can I use this tool to compare battery capacities?

Yes. Convert all battery capacities to the same unit — coulombs or ampere-hours — before comparing. A battery rated at 10 Ah = 36,000 C; a battery rated at 8,000 mAh = 8 Ah = 28,800 C. The 10 Ah battery has greater capacity. For EV batteries rated in kWh (kilowatt-hours, an energy unit rather than a charge unit), conversion to ampere-hours requires the pack voltage: Ah = Wh / V. A 75 kWh pack at 400 V = 187.5 Ah = 675,000 C.

Is the Electric Charge Converter free?

Yes. The converter is free within the daily usage limits shown above. Guest users can perform 25 conversions per day without creating an account. Registering a free ToolsPiNG account increases the daily limit to 100 conversions per day.