Electric Charge Converter
Our free electrical & magnetic converter handles electric charge conversions. See tables, ratios, and examples for quick reference.
Electric Charge Converter
Calculator
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Formula: Converted Value = Input Value x (From Unit Factor / To Unit Factor)
Worked example โ 4000 mAh = 14,400 C
Formula
Converted Value = Input Value x (From Unit Factor / To Unit Factor)
Electric charge conversion works by first converting the input value to the base unit (coulombs) using the source unit factor, then dividing by the target unit factor to get the result. All electromagnetic charge units relate to the coulomb through fixed conversion factors based on physical constants and unit system definitions.
Worked Examples
Example 1: Battery Charge Capacity
Problem:A smartphone battery is rated at 4000 mAh. How many coulombs of charge does it store?
Solution:Charge (C) = mAh x 3.6 Charge = 4000 x 3.6 Charge = 14,400 coulombs This means the battery can deliver 14,400 coulombs before depleting.
Result:4000 mAh = 14,400 C
Example 2: Electron Count from Charge
Problem:A capacitor holds 5 microcoulombs of charge. How many elementary charges is that?
Solution:Number of e = Charge / elementary charge = 5 x 10^-6 C / 1.602176634 x 10^-19 C = 3.122 x 10^13 elementary charges Over 31 trillion electrons are stored on the capacitor plate.
Result:5 uC = 3.122 x 10^13 elementary charges
Frequently Asked Questions
What is a coulomb and how is it defined?
A coulomb (C) is the SI unit of electric charge. It is defined as the amount of charge transported by a constant current of one ampere in one second. One coulomb equals approximately 6.242 x 10^18 elementary charges (electrons or protons). The unit is named after French physicist Charles-Augustin de Coulomb who formulated the law of electrostatic force between charged particles.
How do I convert between coulombs and ampere-hours?
To convert coulombs to ampere-hours, divide the charge in coulombs by 3600, since one ampere-hour equals 3600 coulombs (1 amp flowing for 3600 seconds = 1 hour). Conversely, multiply ampere-hours by 3600 to get coulombs. For example, a battery rated at 2 Ah stores 7200 coulombs of charge. Milliampere-hours (mAh), commonly used for phone batteries, equal 3.6 coulombs each.
What is an elementary charge?
The elementary charge (e) is the magnitude of the electric charge carried by a single proton or electron. Its exact value is 1.602176634 x 10^-19 coulombs, as defined by the 2019 SI redefinition. It is one of the fundamental physical constants of nature. All observable electric charges are integer multiples of this elementary charge, a principle known as charge quantization.
What is a franklin or statcoulomb?
The franklin (Fr), also called the statcoulomb or electrostatic unit of charge (esu), is the unit of electric charge in the Gaussian CGS system. One franklin equals approximately 3.33564 x 10^-10 coulombs. It is defined such that two point charges of one franklin each, separated by one centimeter in vacuum, exert a force of one dyne on each other. While mostly replaced by SI units, it still appears in some theoretical physics literature.
Why are batteries rated in milliampere-hours rather than joules?
Milliampere-hours measure charge capacity, which is the quantity the electrochemistry of a cell most directly limits, and it is independent of the voltage the pack is wired to deliver. Energy in watt-hours is the product of charge in ampere-hours and nominal voltage, so a 4000 mAh cell with a 3.85 volt nominal terminal voltage stores 4.0 x 3.85, about 15.4 watt-hours. Comparing mAh ratings across devices with different pack voltages is misleading; comparing watt-hours is not.
What is the difference between electric charge and electric current?
Charge is a quantity of electricity measured in coulombs, while current is the rate at which charge flows, measured in amperes. One ampere is one coulomb per second, so current equals charge divided by time. A steady 2 amperes flowing for 30 seconds transports 60 coulombs. The distinction mirrors volume and flow rate in a pipe: coulombs answer how much has passed, amperes answer how fast it is passing at this instant.
How does Faraday's constant link charge to moles in electrochemistry?
Faraday's constant is the charge carried by one mole of electrons, approximately 96,485 coulombs per mole, and it follows from multiplying Avogadro's number by the elementary charge. In electrolysis and electroplating, the mass deposited equals the total charge passed multiplied by the molar mass, divided by the number of electrons per ion and by Faraday's constant. That relationship lets a plating current and time be translated directly into a deposited mass, which is the basis of coulometric analysis.
How much charge does a capacitor hold at a given voltage?
Charge equals capacitance multiplied by voltage, with capacitance in farads, voltage in volts and the result in coulombs. A 470 microfarad capacitor charged to 12 volts holds 470 x 10^-6 x 12, which is 5.64 x 10^-3 coulombs, or 5.64 millicoulombs. Because practical capacitance values sit in the microfarad and picofarad range, the resulting charges land in millicoulombs and nanocoulombs, which is why those submultiples appear so often in electronics work.
What does it mean that charge is quantised?
All freely observable electric charge occurs in whole-number multiples of the elementary charge, so no isolated particle carries a fraction of it. Quarks do carry fractional charges of one third and two thirds, but they are confined inside composite particles whose totals remain integer multiples. At everyday scales the granularity is invisible: one coulomb corresponds to roughly 6.24 x 10^18 elementary charges, so charge behaves as a smoothly variable quantity in circuit analysis.
How is the coulomb defined now that the SI has been redefined?
Since the 2019 revision of the SI, the elementary charge is fixed by definition at exactly 1.602176634 x 10^-19 coulombs, and the ampere follows from that fixed value together with the definition of the second. The coulomb is then the derived unit equal to one ampere-second. Previously the ampere was defined through the force between two current-carrying conductors, and the elementary charge was an experimentally measured quantity carrying an uncertainty.
References
Reviewed for accuracy by Manoj Kumar, Mathematics Educator ยท Editorial policy
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