How do you get power factor?

Single phase PF = Input Watts/Volts x Amps. Three phase PF =Input Watts/Volts x Amps x1.732.

Additional Answer

You can determine the power factor of a circuit using three instruments: a voltmeter, and ammeter, and a wattmeter.

Multiplying the voltmeter reading by the ammeter reading will supply the value of the apparent power in volt amperes. The wattmeter reading will supply the value of the true power in watts.

Divide the number of watts by the number of volt amperes, and that will indicate the power factor of the circuit.