How to use the electric charge converter
- Type the amount in Value. The default is 5,000.
- Choose its unit in From, for example milliampere-hours.
- Choose the unit you need in To, for example coulombs. The result appears at once.
- The table under the answer gives the same charge in all 11 units. Swap From and To with the arrow button.
What it does and when to use it
Electric charge is how much electricity has flowed. Battery makers state it in mAh or Ah, physics and chemistry use coulombs, electrochemists use faradays, and particle physics counts elementary charges (the charge of one proton).
Use the converter to compare a phone battery in mAh with a car battery in Ah, to put a battery capacity into coulombs for a physics problem, or to find how many electrons pass in a circuit. If you know the current and the time instead, multiply amps by seconds to get coulombs; the current converter helps with mA or µA, and the Ohm’s law calculator finds the current from voltage and resistance.
How it works
Every unit is stored in coulombs.
| Unit | Coulombs | Definition |
|---|---|---|
| ampere-minute | 60 | 1 A for 60 s |
| milliampere-hour | 3.6 | 0.001 A for 3,600 s |
| ampere-hour | 3,600 | 1 A for 3,600 s |
| faraday | 96,485.3321233 | e × Nᴀ |
| abcoulomb | 10 | CGS-EMU unit |
| statcoulomb | 3.33564095198 × 10⁻¹⁰ | 0.1 ÷ c |
| elementary charge | 1.602176634 × 10⁻¹⁹ | exact since 2019 |
The elementary charge (1.602176634 × 10⁻¹⁹ C), the Avogadro constant (6.02214076 × 10²³ per mole) and the speed of light (299,792,458 m/s) are exact defining constants in the SI Brochure, so every factor here is exact or derived exactly. Results show 12 significant figures.
Worked examples
A phone battery. 3,000 mAh = 3 ampere-hours, which is 10,800 coulombs or about 0.112 faradays.
A 20,000 mAh power bank. That is 72,000 coulombs (20 Ah, 1,200 ampere-minutes).
Counting electrons. 1 coulomb = 6.241509e+18 elementary charges, about 6.24 billion billion.
Limits and tips
- Real capacity is less than the label when a battery is old, cold or drained fast. The converter only changes units.
- Power banks often quote the internal cell’s mAh at about 3.7 V, while the USB output is at 5 V or more, so the mAh you get out at the higher voltage is lower.
- Very large or small values switch to scientific notation (such as 6.74083e+22).
Frequently asked questions
Is mAh a measure of energy?
How many coulombs are in 1 mAh?
What is a faraday?
Why does another source give 96,485.31 C for a faraday?
What are abcoulombs and statcoulombs?
Sources
- SI Brochure: The International System of Units (SI), 9th edition — BIPM, accessed 2026-10-08
- NIST Guide to the SI, Appendix B.8: Factors for units listed alphabetically — NIST, accessed 2026-10-08
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