A portable system for non-destructively measuring amount of coating on a metallic substrate based upon infrared absorbance includes a portable, hand-held measurement unit housed in a pistol-gripped case and an optical sensing unit that has an infrared source and a detector. The infrared source is configured to transmit infrared energy toward a metallic substrate having a coating thereon. The infrared energy passes through the coating, reflects off a surface of the substrate, passes back through the coating, and is detected by the detector. A processor correlates amount of infrared absorbance in the coating to amount of the coating. A base unit holds the hand-held measurement when not in use and charges a battery of the hand-held measurement unit. The base unit includes connectors for uploading and downloading data from and to the hand-held measurement unit and for communicating with an optional host computer.