Charge Converter

Convert electric charge between coulombs, ampere-hours, and related units, explaining what electric charge actually measures.

Electric Charge Is a Quantity, Current Is a Rate

Electric charge measures a fundamental physical quantity, the amount of electricity a body or system carries, distinct from electric current, which measures the rate at which that charge is moving past a point, a distinction exactly parallel to the difference between distance and speed, or volume and flow rate, covered elsewhere in this set of converters. The coulomb, the SI unit, is defined through the electric current unit, the ampere, specifically as the amount of charge that passes a point when a current of one ampere flows for one second, which is exactly why the coulomb and the ampere-hour, a more everyday-familiar charge unit seen on battery specifications, both describe charge quantity built from combining current and time, just using different time increments, seconds for the coulomb and hours for the ampere-hour. This is precisely why a battery’s capacity rating in ampere-hours tells you how much total charge it can deliver, and multiplying that ampere-hour figure by 3,600 converts it into the equivalent coulomb figure, the same fixed number of seconds in an hour that connects every other charge-related unit built on that same underlying current-times-time relationship.