Surface area of cubes, cuboids, spheres, cylinders, cones and pyramids.
All dimensions must use the same unit — the surface area comes out in square units and the volume in cubic units.
Surface area (square units)
SphereHow to use this tool
Pick the shape from the list — cube, cuboid, sphere, cylinder, cone or square pyramid. Only the dimensions that shape needs are shown.
Enter the dimensions, all in the same unit. Mixing centimetres and metres is the most common mistake — keep one unit throughout.
The surface area is the headline result, with the volume, the exact formula used and useful extras (slant height, diagonals, base area) underneath.
The formula shown for your shape is the one to copy into homework or a quote — it changes with the shape you picked.
Formula & worked example
Worked examples: a sphere of radius 3 has surface area 4π×3² = 113.0973 and volume 113.0973 (the two coincide at r = 3). A cube of side 3 has surface area 6×3² = 54 and volume 27. A cylinder of radius 3 and height 5 has surface area 2π×3×(3+5) = 150.7964 and volume 141.3717. A cone of radius 3 and height 4 has slant height 5, surface area π×3×(3+5) = 75.3982 and volume 37.6991.
Limitations — read this before you rely on it
The pyramid here is a square pyramid (square base, apex centred above it); rectangular pyramids and other pyramids need a different formula. The cone is a right circular cone, not an oblique one. All dimensions must share one unit: if you enter radius in centimetres and height in metres, the answer will be meaningless. Results are rounded to 4 decimals for display.
Frequently asked questions
A surface area calculator finds the total area of the outside of a 3D shape. Pick the shape — cube, cuboid, sphere, cylinder, cone or square pyramid — enter its dimensions, and it returns the surface area, the volume and the formula used, so you can check the working.
Surface area of a sphere = 4πr². For radius 3: 4 × π × 9 = 113.0973. Note the volume (4πr³ ÷ 3) is also 113.0973 at radius 3, but that is a coincidence of r = 3, not a general rule.
Surface area of a cylinder = 2πr(r + h) — that is the two circular ends plus the curved side unrolled into a rectangle. For radius 3 and height 5: 2π × 3 × 8 = 150.7964.
First find the slant height with Pythagoras: slant = √(r² + h²). Then surface area = πr(r + slant). For radius 3 and height 4, the slant is 5 and the surface area is π × 3 × 8 = 75.3982.
Yes — surface area is for 3D shapes, in square units, while plain area (for example the area of a square) is for flat 2D shapes. A cube has a surface area; a square has an area. The two are often confused in search, so this calculator keeps them separate.