A cuboid whose length, breadth and height are equal is called a cube. The Curved surface area of cuboid is the sum of the areas of its six faces. The surface area is the total area of all the faces of a 3D shape. CSA of a cuboid is calculated using the given Curved Surface Area (CSA) Of Cuboid Formula. First add both length and breadth, then multiply by 2 with Height. Finally multiply both the answers to get Curved Surface Area of cuboid.