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Surface Area Calculator

Math

Calculate the surface area and volume of cubes, spheres, cylinders, cones, and rectangular prisms. Enter dimensions for precise 3D shape measurements.

Reviewed by the thecalcu.com team · Last updated August 1, 2026

Surface Area

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Volume
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What is a Surface Area?

A Surface Area Calculator works out the total area covering the outside of a 3D shape, cube, sphere, cylinder, cone, or rectangular prism, based on its dimensions, along with the shape's enclosed volume. Surface area calculations come up whenever a real-world task involves covering, painting, or wrapping a three-dimensional object, where simply knowing how much space something occupies (its volume) isn't the figure you actually need.

This calculator handles five common 3D shapes in one place, applying the correct surface area formula for whichever you select. It's the surface-area-focused companion to the Volume Calculator, which covers the same shapes but highlights volume as the primary result.

Why Use a Surface Area Calculator?

Surface area formulas differ meaningfully between shapes, a cone's formula requires calculating a slant height first, while a cube's is a simple square-and-multiply, and mixing up which formula applies to which shape is a common source of errors when working by hand. An incorrect surface area estimate can lead to ordering too much or too little material for a real project.

This calculator applies the right formula automatically based on the shape selected, removing that risk entirely. Someone working out how much paint a cylindrical water tank needs, or a student checking a geometry assignment, gets an accurate answer immediately rather than re-deriving the formula from scratch, the same convenience the Circle Calculator offers for 2D circle measurements.

Who Should Use This Calculator?

  • Students and teachers working through 3D geometry problems involving surface area of cubes, spheres, cylinders, or cones.
  • DIY and home improvement planners estimating paint, coating, or wrapping material needed to cover a 3D object.
  • Packaging designers calculating the material needed to wrap or construct a box or cylindrical container.
  • Construction and manufacturing professionals estimating surface treatment requirements for tanks, pipes, or other shaped components.
  • Engineering and science students needing quick surface area checks alongside related geometry tools.

What Insights Does the Surface Area Calculator Give You?

The calculator returns both core measurements for whichever shape you select:

  • Surface Area, the total area of the shape's outer surface, in square units, the figure needed for any covering, painting, or wrapping task.
  • Volume, the total three-dimensional space the shape encloses, in cubic units, useful as a secondary reference if you also need to know capacity.

Because both figures come from the same set of dimensions, you get a complete picture of the shape without running two separate calculations.

How to use this Surface Area calculator

  1. Select the Shape you want to calculate, Cube, Sphere, Cylinder, Cone, or Rectangular Prism.
  2. Enter Dimension 1, the side length for a cube, or the radius for a sphere, cylinder, or cone.
  3. For cylinders and cones, enter Dimension 2 as the height.
  4. For a rectangular prism, enter all three dimensions, length, width, and depth.
  5. Read the Surface Area result, the primary figure for most covering or painting tasks.
  6. Check the Volume result if you also need to know the shape's capacity.

Formula & Methodology

Each shape uses its own standard surface area formula:

- Cube: SA = 6s², Volume = s³
- Sphere: SA = 4πr², Volume = (4/3)πr³
- Cylinder: SA = 2πr² + 2πrh, Volume = πr²h
- Cone: SA = πr² + πr × slant height (slant height = √(r² + h²)), Volume = (1/3)πr²h
- Rectangular Prism: SA = 2(lw + lh + wh), Volume = l × w × h

Worked example: for a cone with radius 3 and height 4:
- Slant height = √(3² + 4²) = √25 = 5
- Surface Area = π × 3² + π × 3 × 5 = 28.3 + 47.1 ≈ 75.4 square units
- Volume = (1/3) × π × 3² × 4 ≈ 37.7 cubic units

Frequently Asked Questions

The surface area of a cube is calculated as SA = 6s², where s is the length of one side, since a cube has six identical square faces. For a cube with a 4 cm side, the surface area is 6 × 4² = 96 square centimetres.
A sphere's surface area is calculated as SA = 4πr², where r is the radius. This represents the total area of the sphere's curved outer surface, with no flat faces or edges.
A cylinder's total surface area is SA = 2πr² + 2πrh, combining the area of its two circular ends (2πr²) with the area of its curved side (2πrh), where r is the radius and h is the height.
A cone's surface area is SA = πr² + πr × slant height, combining the circular base (πr²) with the curved lateral surface (πr × slant height). The slant height is calculated separately as √(r² + h²), using the radius and vertical height.
Surface area measures the total area covering the outside of a 3D shape (in square units), while volume measures the space enclosed inside it (in cubic units). This calculator shows both together, since many tasks, like painting a tank that also needs a capacity check, need both figures.
A rectangular prism's (box's) total surface area is 2(lw + lh + wh), where l, w, and h are the length, width, and height. Select 'Rectangular Prism' and enter all three dimensions to get the result.
A cone's volume only depends on its base radius and vertical height, but its surface area depends on the slant height, the distance along the cone's slanted side from the base edge to the apex, since that's the dimension that actually forms the curved surface. The calculator computes the slant height automatically from the radius and height you enter.
Both tools cover the same five shapes and calculate the same two figures, but this Surface Area Calculator highlights surface area as the primary result, while the [Volume Calculator](/volume-calculator/) highlights volume instead. Use whichever matches what you're primarily trying to find.
Surface area calculations come up whenever you're covering, painting, wrapping, or coating a 3D object, for example, working out how much paint a cylindrical tank needs, or how much wrapping paper covers a box. Volume, by contrast, matters when you're filling the shape rather than covering it.
Yes, surface area results are in square units matching whatever unit you used for the dimensions (for example, entering centimetres gives a result in square centimetres). Make sure all dimensions use the same unit before calculating for an accurate result.
Also known as
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