Battery Capacity Calculator: Calculate Battery Energy in Watt-hours or Joules

The Battery Capacity Calculator is a tool designed to calculate the capacity of a battery based on specific parameters. It assists in determining the amount of energy stored in a battery, measured in watt-hours (Wh) or joules. This calculator is widely used in various fields, including electronics, renewable energy systems, electric vehicles, and portable devices.


The Battery Capacity Calculator serves multiple purposes. Here are some examples of its usage:

  1. Electronics: It helps determine the battery capacity required for electronic devices like smartphones, laptops, or tablets, considering their power consumption and desired runtime.

  2. Renewable Energy Systems: In solar or wind power systems, the calculator assists in sizing the battery bank by considering the daily energy consumption, backup duration, and system efficiency.

  3. Electric Vehicles: This tool is valuable for estimating the battery capacity needed to achieve a specific driving range in electric cars or other electric vehicles.


The Battery Capacity Calculator requires the following parameters to estimate the battery capacity:

  1. Voltage (V): The voltage represents the electrical potential difference across the battery terminals and is measured in volts (V). It indicates the force or pressure at which electrical energy is delivered by the battery.

  2. Battery Capacity: Battery capacity refers to the amount of charge a battery can store and is typically measured in ampere-hours (Ah) or watt-hours (Wh). It represents the total energy the battery can deliver before requiring recharging.

  3. Watt-hours (Wh) or Joules (J): These units measure energy. Watt-hours represent the amount of energy consumed or delivered in an hour at a certain power level, while joules represent the total energy delivered or consumed by a device or system.


The relationship between Voltage (V), Battery Capacity, and Watt-hours (Wh) or Joules (J) can be described as follows:

Battery Capacity (in Wh or J) = Voltage (in V) * Battery Capacity (in Ah)

This equation calculates the energy capacity of a battery by multiplying its voltage by its capacity in ampere-hours. The result will be in watt-hours (Wh) or joules (J), depending on the units used for the voltage and battery capacity.

It's important to note that the voltage parameter is essential for estimating the energy capacity, as different batteries have different voltage ratings.


It is believed that these calculations are accurate, but not guaranteed. Use at your own risk!