Surface Area Calculator
Shape
Surface Area150.0000
Surface area is the total area of the outer faces of a three-dimensional shape — the amount of material needed to cover it. This calculator computes the surface area of a cube, sphere, cylinder, or cone from the relevant dimensions, and for the cylinder and cone it also separates out the lateral (side) area from the total.
Formula
Cube 6s² · Sphere 4πr² · Cylinder 2πr(r + h) · Cone πr(r + l)
- s
- Side length of the cube
- r
- Radius of the sphere, cylinder, or cone
- h
- Height of the cylinder
- l
- Slant height of the cone (not its vertical height)
How it works
- Choose a shape: cube (enter side length), sphere (radius), cylinder (radius and height), or cone (radius and slant height).
- Each shape uses its standard surface-area formula — for example 6s² for a cube and 4πr² for a sphere.
- For a cylinder the total is 2πr(r + h) with a lateral area of 2πrh; for a cone the total is πr(r + l) with a lateral area of πrl. Any non-positive dimension is invalid and returns no result.
Worked examples
Find the surface area of a cylinder with radius 3 and height 5.
- Total = 2πr(r + h) = 2π × 3 × (3 + 5) = 2π × 3 × 8 = 48π.
- 48π ≈ 150.7964.
- Lateral area = 2πrh = 2π × 3 × 5 = 30π ≈ 94.2478.
Total surface area ≈ 150.80, lateral area ≈ 94.25
Find the surface area of a sphere with radius 4.
- Surface area = 4πr² = 4π × 4² = 4π × 16 = 64π.
- 64π ≈ 201.0619.
- A sphere has no separate lateral area.
Surface area ≈ 201.06
Frequently asked questions
- What is the difference between total and lateral surface area?
- Total surface area covers every face including the top and bottom, while lateral surface area is just the curved or slanted side. The calculator reports both for cylinders and cones; for a cube and sphere only the total is shown.
- Why does the cone need a slant height instead of vertical height?
- The lateral surface of a cone wraps along its slanted edge, so its area depends on the slant height l, not the vertical height. If you only know the vertical height h and radius r, the slant height is √(r² + h²).
- What units does the result use?
- Surface area is always in square units of whatever you entered — if your dimensions are in centimetres the area is in square centimetres. The calculator does not assume a unit; it simply works in whatever you provide.
- How is surface area different from volume?
- Surface area measures the two-dimensional skin of a shape (in square units), while volume measures the three-dimensional space inside it (in cubic units). For the same shapes you can compute the interior space with the volume calculator.