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Cube Volume Calculator

Find the volume of a cube from its side length using V = s³.

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How to use

  1. 1.Enter the side (edge) length of the cube in the input box, using any unit you like (cm, m, inches).
  2. 2.Read the cube volume V = s³, calculated live as you type — no button to press.
  3. 3.Check the extra measurements below: surface area (6s²), face diagonal (s√2), and space diagonal (s√3).

About Cube Volume Calculator

The volume of a cube is V = s³, where s is the length of one edge. Because every side of a cube is equal, you only need a single measurement: cube the side length and you have the volume. For example, a cube with a 5 cm side holds 5 × 5 × 5 = 125 cubic centimetres (cm³). This calculator does that instantly and shows the working, so you can check homework, size a container, or plan a shipment in seconds.

A cube is a special right rectangular prism where length, width, and height are identical, which is why the general box formula (l × w × h) simplifies to s × s × s. That symmetry also makes its other measurements easy to derive from the same side length. The surface area of a cube is 6s², because a cube has six identical square faces, each with area s². A cube with a 5 cm side therefore has a surface area of 6 × 25 = 150 cm².

Two diagonals matter as well. The face diagonal runs corner to corner across one square face and equals s√2 (about 1.414 × s), from the Pythagorean theorem applied to two equal sides. The space diagonal runs through the interior of the cube from one vertex to the opposite vertex and equals s√3 (about 1.732 × s); it is the longest straight line that fits inside the cube, which is handy when you need to know whether a long object will fit diagonally.

To go the other way — from a known volume back to the side length — take the cube root: s = ∛V. A cube that holds 125 cm³ has a side of ∛125 = 5 cm. This is useful when a container must hold a set volume and you need its edge length. Volume also scales with the cube of the side, so small length changes have a large effect: doubling the side multiplies the volume by 2³ = 8, and tripling it multiplies the volume by 27. Surface area, by contrast, grows only with the square of the side, so bigger cubes have proportionally less surface area for their volume.

Keep your units consistent: if the side is in centimetres, the volume comes out in cubic centimetres (cm³); metres give cubic metres (m³); inches give cubic inches. Volume is always a cubed unit, surface area a squared unit, and diagonals a plain length. For capacity, remember that 1 litre equals 1,000 cm³, so a cube with a 10 cm side holds exactly one litre. Typical uses include finding the capacity of a cubic tank or box, estimating material for a solid block, and solving geometry problems. All calculations run entirely in your browser — nothing is uploaded — and update live as you type, including decimals and very large or very small side lengths.

Frequently asked questions

What is the formula for the volume of a cube?
The volume of a cube is V = s³, where s is the length of one edge. Since all sides are equal, you just multiply the side by itself twice: s × s × s. For example, a cube with a 4 cm side has a volume of 4³ = 64 cm³.
How do you calculate the surface area of a cube?
A cube has six identical square faces, so its total surface area is 6s², where s is the side length. For a cube with a 4 cm side, each face is 4² = 16 cm², and the total surface area is 6 × 16 = 96 cm².
What are the face diagonal and space diagonal of a cube?
The face diagonal crosses one square face and equals s√2 (about 1.414 × s). The space diagonal runs through the middle of the cube between opposite corners and equals s√3 (about 1.732 × s), the longest straight line that fits inside the cube.
What is the difference between a cube and a rectangular box (cuboid)?
A cube is a special box where length, width, and height are all equal, so V = s³. A rectangular box (cuboid) can have three different edge lengths, so its volume uses V = length × width × height. Every cube is a cuboid, but not every cuboid is a cube.
What units does the cube volume come out in?
Volume takes the cube of whatever unit you enter for the side. A side in centimetres gives cubic centimetres (cm³), metres give cubic metres (m³), and inches give cubic inches (in³). Keep the side length in a single consistent unit for a correct result.

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