Calculator online for a circular cylinder . Calculate the unknown defining surface areas, height, circumferences, volumes and radii of a capsule with any 2 known variables. Online calculators and formulas for a cylinder and other geometry problems. Learn what a cylinder is, how to classify it into different types, and how to calculate its volume and surface area. See diagrams, definitions, and solved problems for cylinders. A cylinder is a special three-dimensional solid geometrical shape that consists of two flat circles at either end joined by a curved surface. Learn about cylinder , a three-dimensional shape with two parallel circular bases and a curved surface. Find out its formulas for surface area and volume, and see examples and FAQs.