Amp hour is the rating used to tell consumers how much amperage a battery can provide for exactly one hour.

In small batteries, the amp hour rating is usually given in milli-amp hours, mAh.

**Formula to calculate battery amp hours.**

The watt-hour is a unit of energy equal to one watt of output for an hour.

Volts is the measure of the potential energy difference between two points in a circuit.

**Example:**

Suppose you were to measure the amp hours of a 12 volts battery whose watt hour is 1200.

Therefore, the battery’s watt hour is 100.