What is the formula for calculating power factor?

To understand why the formula for calculating power factor is based on the relationship between watts, volts, and amps, we need to delve into the concept of power factor itself. Power factor is defined as the ratio of real power, which is measured in watts, to the apparent power, which is a product of the voltage and current in an electrical system.

The correct formula can be derived from the definition of apparent power:

Apparent Power (in VA) = Volts x Amps.

Real Power (in watts) is the power that actually performs work in the circuit. To calculate the power factor, we take the real power (in watts) and divide it by the apparent power (in volt-amperes), which gives us:

Power Factor = Real Power (Watts) / Apparent Power (Volts x Amps).

By rearranging that formula, you can arrive at the form that indicates the relationship you provided: Watts / (Volts x Amps). When considering standard expressions used in practice, power factor is often expressed in terms of watts over the product of volts and amps, reinforcing the idea that the real power consumed by a device or circuit, divided by the apparent power, gives insight into the efficiency of the electrical