A wireless power transmitter is provided. The wireless power transmitter includes a power source configured to provide direct current (DC) power, an inverter configured to receive the DC power from the power source, invert the DC power into alternating current (AC) power, and output the AC power, a coil configured to generate a magnetic field based on an input of the AC power, a sensor configured to measure a voltage of the AC power output from the inverter and a current of the AC power output from the inverter, and at least one processor configured to identify an external voltage applied to a load of an electronic device based on the voltage of the AC power and the current of the AC power, wherein the electronic device is configured to be wirelessly charged using the magnetic field.