A portable air compressor includes a frame, a compressor unit coupled to the frame, and an air tank for storing compressed air generated by the compressor unit. The air tank is coupled to the frame. A battery compartment coupled to the frame. The battery compartment defines an opening and a battery receptacle within the opening. The portable air compressor also includes a battery pack selectively electrically connectable to the battery receptacle, an outlet port protruding from the battery compartment, a tank gauge on the battery compartment, a pressure regulator between the air tank and the outlet port for regulating the pressure of air supplied from the outlet port, an actuator on the battery compartment for adjusting the regulated pressure of air supplied from the outlet port, and a switch on the battery compartment for turning the compressor unit on and off.