Math

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Cube Calculator.

Calculate a cube's surface area, volume, and space diagonal from its edge.

On-device calculationNo signup
01

Set your values

Results update as you type.

Surface area: 96 units²

Surface area

0.000000units²
Volume: 64 units³

Volume

0.000000units³
Space diagonal: 6.928203 units

Space diagonal

0.000000units

Results update automatically as you type.

Use Cases

Packaging and Shipping

Determine the surface area and volume of cubic boxes to estimate material needs and shipping costs.

Example: A cube with edge 2 feet has surface area 24 sq ft and volume 8 cu ft.

Architecture and Design

Calculate the space diagonal of cubic structures to ensure clearance or fit within a space.

Example: For a cube with edge 5 meters, the space diagonal is about 8.66 meters.

Frequently Asked Questions

How do I calculate the volume of a cube?
Enter the edge length in the provided field. The calculator will compute the volume as edge length cubed (a³). For example, if the edge is 3 units, the volume is 27 cubic units.
What is the space diagonal of a cube?
The space diagonal is the longest diagonal inside the cube, connecting opposite corners. It is calculated as edge length times the square root of 3 (a√3). For a cube with edge 2 units, the space diagonal is approximately 3.464 units.
Can I use any unit for the edge length?
Yes, you can enter the edge length in any unit (e.g., cm, inches, feet). The results will be in corresponding square units for surface area, cubic units for volume, and the same unit for the diagonal.

Tips & Common Mistakes

Tips

  • Ensure the edge length is positive; negative values are not valid for a cube.
  • Use consistent units for edge length to get correct surface area and volume units.
  • The space diagonal is always longer than the face diagonal; it's the longest straight line inside the cube.
  • For quick mental checks, remember surface area = 6a² and volume = a³.

Common Mistakes to Avoid

  • Forgetting to cube the edge length for volume; using a² instead of a³.
  • Using the face diagonal formula (a√2) instead of the space diagonal (a√3).
  • Mixing units (e.g., entering edge in cm but expecting results in inches).

Last updated: August 13, 2026