A method for determining a value of arc voltage in a welding system, the welding system including a switch mode power supply and a controller that controls operation of the switch mode power supply, the method including, during an active power delivery stage of the switch mode power supply sensing a first internal voltage (V20) within the switch mode power supply prior to an internal inductor and a first output voltage (V21) of the switch mode power supply; during a freewheeling stage of the switch mode power supply sensing a second internal voltage (VF) within the switch mode power supply prior to the internal inductor and a second output voltage (V22) of the switch mode power supply; and determining the value of arc voltage based on the first internal voltage, the first output voltage, the second internal voltage, and the second output voltage.