Apparent power is the combined power value that is obtained by allowing for the different values of current and voltage. Essentially, the measure of apparent power is achieved by multiplying the applied voltage to the current generated. Most electrical systems operate by the use of apparent power.

There are a few basic understandings about the nature of apparent power that help to define the nature of the power. Components of both reactive and real power must be present in order for apparent power to exist. That is, the load must be both reactive and resistant in order for the flow of apparent power to take place, and thus create a means for measuring the nature of the generated power. In addition to the presence of resistant and reactive loads, it is also important to determine the watts involved in the current as well. Just as in determining the rate of any complex power, knowing the watt value is key to understanding the nature of apparent power.

In the actual calculation of apparent power, the number of volts is multiplied by the number of amps. Results of the calculation are presented in terms of volt-amperes reactive and real power. This simple multiplication of voltage and current makes it possible to ensure that the flow of apparent power is sufficient to operate devices designed for a given level of power, as well as ensure the flow of apparent power can be handled by the components within the device. Within this context, the measure of apparent power is very important to manufacturers, as it allows them to ensure that all products are within the standards applicable within the jurisdiction.

Measuring the flow of apparent power is also critical in the tasks of wiring public buildings and residences properly. Plants must ensure that all electrical wiring and additional components will adequately support the power supply needed to drive large machinery without overloading the circuits or wiring systems. Power suppliers themselves will measure apparent power to make sure that the flow of harnessed energy into homes and other buildings is maintained within the safety standards that apply to the area and type of structure.