HP, short for horsepower, represent how much power a device is capable of putting out. Kilo-volt-amps, abbreviated kVA, measures the apparent power of a circuit and is found by multiplying the voltage times the current in a circuit. In order to convert from the HP capacity of a device to the number of kVA used, you need to know the capacity and the efficiency of the device.
Multiply the amount of HP by 746. For example, if you have 100 HP, you would multiply 100 by 746 to get 74,600.
Multiply the result from Step1 by the efficiency of the device to calculate the number of volt-amps used. For example, if the device is 90 percent efficient, you would multiply 74,600 by 0.9 to get 67,140.
Divide the number of volt-amps used by 1,000 to convert from volt-amps to kilo-volt-amps (kVA). Finishing the example, you would divide 67,140 by 1,000 to get 67.14 kVA.