With the advent of high-temperature-resistant materials in the sheet-metal industry, it is becoming increasingly important to treat the subject of minimum or “critical” bend radius analytically. A simple equation is presented that correlates the minimum bend radius with the percentage reduction of area of the material. The theoretical derivation as well as experimental data are given, with very good agreement between the two. Consequently, it is possible to predict the minimum bend radius for a specific material, provided that the percentage reduction of area, as determined by a standard tensile test, is known. The relationship applies equally well to metals and nonmetals.