Surface Area Calculator
Surface area of 3D shapes.
Input
Result
What is a Surface Area Calculator?
A surface area calculator finds the total area covering the outside of a three-dimensional object. It works for cubes, cylinders, spheres, and other 3D shapes, giving results in square units.
How to calculate surface area manually (the formula)
Cube: SA = 6s2. Cylinder: SA = 2πrh + 2πr2. Sphere: SA = 4πr2. Each formula adds the areas of all faces or surfaces.
Example calculation
Find the surface area of a sphere with radius 6. SA = 4π × 62 = 4π × 36 = 144π ≈ 452.39 square units.
Common mistakes
- Confusing surface area with volume — Surface area uses square units (covering), volume uses cubic units (filling). They measure different things.
- Forgetting to count all faces — A cylinder has two circular ends plus a curved side. Each part contributes to total surface area.
- Using diameter instead of radius — Most formulas use radius. Using the diameter directly without halving it first gives incorrect results.
Frequently asked questions
What is surface area?
Surface area is the total area of all outer surfaces of a three-dimensional object, measured in square units.
How do you calculate the surface area of a cube?
Use SA = 6s\u00b2, where s is the side length. A cube has six identical square faces.
How do you calculate the surface area of a cylinder?
Use SA = 2\u03c0rh + 2\u03c0r\u00b2. The first term is the lateral area, the second is the area of the two circular ends.
How do you calculate the surface area of a sphere?
Use SA = 4\u03c0r\u00b2, where r is the radius. Multiply 4 by pi and the radius squared.
What is the difference between surface area and volume?
Surface area measures the outside covering in square units. Volume measures the interior space in cubic units.
What units are used for surface area?
Surface area is expressed in square units such as in\u00b2, ft\u00b2, cm\u00b2, or m\u00b2.