What is the formula for the surface area of a cube?

The formula is SA = 6a², where a is the length of one side. A cube has 6 identical square faces, so you multiply the area of one face (a²) by 6.

What units does the calculator support?

The calculator supports millimeters (mm), centimeters (cm), meters (m), inches (in), and feet (ft). The result is displayed in square units matching your selection.

What is the difference between total surface area and face area?

A cube has 6 faces. The face area is the area of just one face (a²). The total surface area is the combined area of all 6 faces (6a²).

Can I use decimals for the side length?

Yes. The calculator accepts decimal values such as 3.5 or 12.75. Results are rounded to four decimal places for precision.

Does this work for non-cube rectangular boxes?

No, this calculator is specifically for perfect cubes where all sides are equal. For rectangular boxes (cuboids), the formula is SA = 2(lw + lh + wh).

Surface Area of a Cube Calculator

Enter a side length to instantly calculate the total surface area of a cube using SA = 6a².

Cube Dimensions

Enter the side length of the cube below.

Side Length (a)

Formula Used

SA = 6a²

where a is the side length

Enter a side length to see the result.

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Summary

The Surface Area of a Cube Calculator computes the total surface area of a cube from its side length using the formula SA = 6a². It shows the area of each individual face as well as the combined surface area, and supports multiple units of measurement. All calculations happen instantly in your browser with no data sent to any server.

How it works

Enter the side length of the cube in the input field.
Select your preferred unit (mm, cm, m, in, or ft).
The calculator instantly applies the formula SA = 6a².
Results display the total surface area and the area of one face.
Copy the result or adjust the input to recalculate.

Use cases

Calculate how much paint or material is needed to cover a cube-shaped object.
Solve geometry homework problems involving cube surface area.
Estimate packaging material needed for cube-shaped boxes.
Verify manual calculations for engineering or design projects.
Teach or learn the surface area formula with instant visual feedback.
Compare surface areas across different cube sizes.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu