Charge Converter

What the Charge Converter does

Charge Converter: 1 C = 0.27777778 mAh, so multiply a coulomb value by 0.27777778 to get milliampere hour, or divide to go back. Example: 1 C = 0.27777778 mAh.

This converter reads Value, From and To and produces Result, How it was calculated and Reverse conversion. Change any input and the output follows immediately.

Unit mistakes are quietly expensive. They have wrecked spacecraft and ruined recipes alike. That is usually what brings students converting units for homework here.

The work is done by JavaScript already loaded in your browser, so your input never crosses the network.

Each field is explained further down, along with the method and a worked example that uses the default values.

What do the Charge Converter fields mean?

The Charge Converter uses 3 inputs. Because the form arrives filled, the first useful result costs you zero typing.

How does the Charge Converter work?

Both units are converted through electric charge's base unit (C), so any of the 8 units in the dropdowns can be paired in either direction without loss of accuracy.

Every factor here is the defined one, not a textbook approximation. That matters more than it sounds: rounding a factor early is the usual reason two converters disagree in the fourth decimal place.

Worked example

These are the values the Charge Converter loads by default, and the result it produces from them. Open the tool above and you will find precisely these figures already in place.

Electric charge: coulombs and amp-hours

The coulomb (C) is the SI unit of electric charge, but the everyday unit consumers actually encounter is the milliampere-hour (mAh), the number printed on every phone and laptop battery, and the two connect through a simple relationship: 1 ampere-hour equals exactly 3,600 coulombs.

Worth knowing

• mAh measures charge, not energy, which is a genuinely common point of confusion: two batteries with the same mAh rating but different voltages store different amounts of actual energy, since energy in watt-hours equals the charge in amp-hours multiplied by the voltage (Wh = Ah × V).
• This is why comparing phone or power-bank "capacity" by mAh alone can be misleading if the batteries being compared run at different voltages (most phone batteries run around 3.7 to 4.4 V, but not identically): the mAh figure alone doesn’t fully capture how much usable energy is stored.
• The elementary charge (the charge of a single proton or electron, roughly 1.602 × 10⁻¹⁹ coulombs) is a defining physical constant since the 2019 SI redefinition, and is included in this converter’s underlying unit family as the smallest natural charge unit that exists.

Definitions: BIPM SI Brochure · NIST reference on units

How to use it

1. Set Value.
2. Pick a value for From: the options are Picocoulomb (pC), Nanocoulomb (nC), Microcoulomb (µC), Millicoulomb (mC), Coulomb (C) or Ampere hour (Ah).
3. Pick a value for To: the options are Picocoulomb (pC), Nanocoulomb (nC), Microcoulomb (µC), Millicoulomb (mC), Coulomb (C) or Ampere hour (Ah).
4. Skip the submit button; there is not one. Editing is enough.
5. Check Result, How it was calculated and Reverse conversion on the right.
6. Use Copy Link if you want the same setup again later, or Print for a paper copy.

What this tool does not do

• Factors use the internationally agreed definitions; some industries round them differently.
• Repeated conversions compound rounding, so convert once from the original value where you can.
• Batch work is not supported; each run handles one set of values.
• The result inherits any error in the inputs without flagging it.

Frequently asked questions

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