process of smoothing and compressing a material (notably paper) during production by passing a single continuous sheet through a number of pairs of heated rolls. The rolls in combination are called calenders. Calender rolls are constructed of steel with a hardened surface, or steel covered with fibre; in paper production, they typically exert a pressure of 500 pounds per linear inch (89 kilograms per centimetre). Coated papers are calendered to provide a smooth, glossy finish.

Calendering is also widely used in the manufacture of textile fabrics, coated fabrics, and plastic sheeting to provide the desired surface finish and texture.