Mido

cos φ, where φ is the phase angle difference between voltage and current waveforms in the circuit.

KVA is a masculine and KW is feminine....

Please dont waste our time.. Search for things before you ask a question. There are number of threads regarding this..

Go and do your search and then ask a proper question.

Let me give some basic information.

kW ( real power ) is the amount of power for doing real work or real power is required to perform work.

kVA(apparent power) is the amount of power which only a apart of the avaliable kVA may do work.
kVAr( reactive power) is necessary to assist or support the work being done.

The ratio between kW and kVa is power factor. When voltage and current are in phase it means the power factor is one.
kVa = voltage * Ampere
kW = Voltage * ampere * power factor.

Power delivered to a purely resistive load is determined by multiplying volts by amps (Kw) and is usually dissipated in the form of heat. Power delivered to a reactive load, one with capacitance and/or inductance, (kVA) is determined by Tornado's equation above and describes the power required to create electric and magnetic fields as opposed to just heat.