Systems and methods for adaptive power factor correction are described that utilize a circuit that senses a current or frequency of a line and controls one or more switches to vary the capacitance of the circuit based on the measured current or frequency. Two or more branches can be used to allow for the capacitance of the circuit to be varied over time in response to a change in the measured current or frequency. Using such systems and methods, a high power factor can be maintained even for higher line frequencies and lighter loads.