In parallel boost converters, wiring loss occurs owing to the voltage difference between the converters. This paper proposes a wiring loss reduction method that employs CCM and DCM in a boost chopper. In particular, new approximation methods for the output voltage ripple of the DCM boost chopper are considered. Then, the carrier phase difference used to reduce the wiring loss is derived using the new approximation methods. Finally, the validity of the theory is confirmed by simulation and experimental results. The experimental results show that the wiring loss reduced to about 75% in the CCM and to about 65% in the DCM.