System and methods for high accuracy, non-intrusive current sensing are provided. A system may include two magnetic field sensors configured for differential sensing. The system may further include frontend circuitry configured to remove direct current (DC) offset of the magnetic field sensors, upconvert the outputs of the magnetic field sensors, and filter out at least one frequency component from the up-converted signals. The system may receive output signals from the front-end circuitry corresponding to each sensor. The system may further calculate a differential signal based on the output signals. The system may apply optimal detection based on the differential signal and a reference signal to calculate a measurement of current flow. The system may determine a phase angle measurement between the differential signal and the reference signal to calculate a direction of the current flow in the conductor and output various measurement information related to the detected current.