Watt-hour Calculator

Electrical energy in watt-hours (Wh) is calculated using two primary relationships depending on your known variables. First, energy can be derived from electrical power and time using the formula Energy = Power (Watts) × Time (Hours). Second, energy can be calculated from electrical charge and voltage using the formula Energy = Charge (Amp-hours) × Voltage (Volts). These foundational equations allow you to convert seamlessly between different electrical units.

Imagine you are running a portable camping refrigerator that consumes 60 watts of power for a duration of 5 hours. To find the total energy consumed in watt-hours, multiply the power by the time: 60 W × 5 hours = 300 Wh. Alternatively, if your system operates at a constant 12 volts, you can find the total charge used by rearranging the charge equation: 300 Wh / 12 V = 25 Ah of electrical charge.

Always ensure your time units are in hours rather than minutes or seconds before multiplying by power. When dealing with rechargeable batteries, remember that watt-hours account for system voltage, making them a more reliable metric than amp-hours alone when comparing energy storage across different voltages.