Surface Area Calculator

Surface area is the total area of every face of a 3D shape — what you need for painting, wrapping, coating or material estimates. Pick the shape, enter its dimensions, and get the total surface area with the matching formula.

Results

Assumptions: Cylinder and cone are closed (they include their circular base areas).

Formula

Each shape adds up its faces:
Cube 6s² · Prism 2(lw + lh + wh) · Cylinder 2πr(r + h) · Sphere 4πr² · Cone πr(r + slant)
Cylinder and cone results here are for closed shapes (with their circular bases).

How to use this calculator

  1. Select the shape.
  2. Enter the dimensions it needs — the labels note which each shape uses.
  3. Press Calculate for the total surface area in square units.
Surface Area Calculator — how the calculation works, illustrated
Surface Area Calculator — how the calculation works, illustrated

Worked example

A cube with side 4.

  1. Each face has area 4 × 4 = 16.
  2. A cube has 6 identical faces: 6 × 16 = 96.

Result: The surface area is 96 square units.

Frequently asked questions

Is the cylinder result for an open or closed can?

Closed — it includes both circular ends. For an open-top container, subtract one base (πr²) from the result.

What units is the answer in?

Square units of whatever you entered: inches in → square inches out. Surface area always carries squared units.

Why does a sphere use the same 4πr² as a circle’s area times four?

A sphere’s surface equals exactly four great-circle areas — a classical result of Archimedes, and a handy way to remember the formula.

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