Copper rod is known for its ability to conduct electricity and is commonly used in plumbing, electrical, and engineering applications. We carry copper round stock in 101, 110 Metric, 110, 145, and 182. Our solid copper rod diameters start at 1/16" (.0625) and go up to 6". Metric from 2mm to 20mm. With standard and custom-cut lengths available, Online Metals is the best place to buy copper rod online.