Food cans are identified by their nominal dimensions, diameter * height. (The "nominal" dimensions are somewhat larger than the actual dimensions, as is the case for lumber and some other products.) In the metric world the dimensions are 2- or 3-digit numbers representing dimensions in millimeters. In traditional U.S. nomenclature, the dimensions are stated as 3-digit numbers, with the first digit representing inches and the remaining two digits representing 16ths of an inch. A common can for fruits and vegetables, for example, is designated 83 * 116 in metric terminology, or 307 * 409 (3-7/16 * 4-9/16) in traditional terminology. If only one number is mentioned it is the diameter; thus a "404" can has a nominal diameter of 4-4/16 = 4.25 inches and a "65" can has a nominal diameter of 65 millimeters. Link: chart of standard can sizes with metric and traditional designations, from Dantraco Associates