What are the dimensions of a d12 die?

A standard dodecahedron (d12) die typically has 12 faces, each shaped as a regular pentagon. Its dimensions can vary slightly depending on the manufacturer, but a common size is about 20 millimeters (0.79 inches) across the widest point. The edge length is usually around 16 millimeters (0.63 inches). Overall, it is designed to fit comfortably in the hand for rolling.