Key takeaways
- The surface area of a cube is A = 6 × a², six identical square faces.
- a² alone only gives the area of one face — multiply by 6 for the whole cube.
- Doubling the edge makes the surface area four times bigger, not twice.
- Surface area covers the outside; volume measures the space inside.
In this guide
What is the surface area of a cube?
A cube has six identical square faces. Surface area is the total area of all six faces combined, measured in square units such as cm² or m². This is different from volume, which measures the space inside.
Why does the surface area of a cube matter?
It tells you exactly how much wrapping paper, cardboard, or paint covers a cube-shaped object completely.
A cube with a 5 m edge has a surface area of6 × 5² = 150 m². Double the edge to 10 m, and the surface area isn't 300 m² — it's6 × 10² = 600 m², four times as much.
The formula
| Symbol | What it means | Example |
|---|---|---|
| A | The total surface area you want to find | 150 m² |
| a | The edge length: any one edge, since all are equal | 5 m |
| 6 | Accounts for the cube's six identical square faces | — |
How to find the surface area step by step
- 1Measure one edge of the cube.
- 2Square the edge length. This gives the area of one face.
- 3Multiply that face area by 6. Since a cube has six faces.
- 4Add square units. Such as cm² or m².
Now try it yourself. Change the edge length in the calculator below and watch the surface area update, with every step shown.
Try it yourself
Pre-filled with the example — change any value.
Common mistakes to avoid
- Confusing surface area with volume. Surface area covers the outside, in square units; use the volume of a cube calculator instead if you need the space inside.
- Mixing up cube and square area. A cube's surface is made of six squares, but the total surface area formula already accounts for all six.
- Using the wrong edge length. All six faces are identical, so a single accurate measurement is all you need.
Tips and tricks
- Wrapping a gift box? Add a little extra paper beyond the calculated total for folds and overlaps.
- To find the space inside instead of the outer covering, use the volume of a cube calculator.
Where you'll use it in real life
- Gift wrapping: working out how much wrapping paper covers a cube-shaped box.
- Packaging: estimating cardboard needed to build a box.
- Construction: calculating paint needed to cover a cube-shaped block or structure.
- Manufacturing: designing material use for cube-shaped storage containers.
Quick summary
To find the surface area of a cube, square the edge length to get one face's area, then multiply by 6 for all six faces. Doubling the edge quadruples the surface area, not doubles it. Use the calculator above to check your own cube instantly.
Worked example
You're painting a cube-shaped storage shed with sides of 5 meters. How much surface area do you need to cover with paint?
- 01A = 6a²
- 02A = 6(5)²
- 03A = 6(25)
- 04A = 150 m²
These numbers are pre-filled in the calculator above.
Frequently asked questions
How do I find the surface area of a cube from its volume?
Take the cube root of the volume to get the edge length, then use A = 6a².
What's the difference between surface area and volume of a cube?
Surface area (6a²) is the total area of all six faces, in square units. Volume (a³) is the space inside, in cubic units. Use the [volume of a cube calculator](/calculator/volume-cube) for the space inside.
Why is the formula 6a² and not just a²?
a² only gives the area of one square face. A cube has six identical faces, so the total surface area multiplies that single-face area by 6.
Does doubling the edge length double the surface area?
No, it quadruples it. Since the edge is squared in the formula, doubling it multiplies surface area by 2 × 2 = 4.
