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Volume of solids

Math & numbers
Everyday

How much does this shape hold?

Volume and surface area of boxes, cylinders, spheres, cones and seven more solids, in litres and gallons too.

m

m

m

Volume

24 m³

Holds 24,000 L · surface 52 m²

Box (cuboid) sketched in proportion: volume 24 m³.

Formula and capacity

Formula
V = l × w × h, surface 2 × (lw + lh + wh)
US gallons
6,340.13 US gal
Imperial gallons
5,279.26 imp gal

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Volume and surface area of boxes, cylinders, spheres, cones and seven more solids, in litres and gallons too.

How to use

  1. Pick the solid.
  2. Enter its measurements and choose the unit beside any field: every length follows it.
  3. Read the volume, what it holds in litres or gallons and its surface area; the sketch shows the solid in proportion.

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How it works

Volume is how much space a solid fills, counted in cubes of the length unit: a box 4 m long, 3 m wide and 2 m high holds 4 × 3 × 2 = 24 cubes of 1 m × 1 m × 1 m, so 24 m³. A cubic metre is 1 000 litres, so that box holds 24 000 litres of water. The surface area is the total area of its faces, what you would paint or wrap.

Solids with a constant cross-section, such as a box or a cylinder, are the base area times the height: a cylinder is π × r² × h. Pointed solids hold a third of that: a cone is π × r² × h / 3 and a pyramid l × w × h / 3. A sphere is 4/3 × π × r³; a sphere 1 m across (r = 0.5 m) holds about 0.52 m³, or 524 litres. Source: CRC Standard Mathematical Tables and Formulae.

Every volume here is exact for the ideal shape. The ellipsoid's surface has no simple formula and uses Knud Thomsen's approximation, within about 1 %. Real containers have walls, sloping floors and rounded corners, so measure the inside and use an average depth.

Worked example

What is the volume of a box measuring 2 × 3 × 4 m?

  1. V = 2 × 3 × 4 = 24 m³.

The volume is 24 m³.

Frequently asked questions

How many litres are in a cubic metre?

Exactly 1 000. A litre is a cube 10 cm on each side, and ten of those fit along each edge of a cubic metre.

How do I work out the volume of a pool with a sloping floor?

Use the average depth: add the shallow and the deep end and halve it. For a pool 1 m deep at one end and 2 m at the other, use 1.5 m.

Why is a cone a third of a cylinder?

A cone narrows to a point, so its slices shrink with the square of the height; adding them up gives exactly one third of the cylinder with the same base and height.

Is a US gallon the same as an imperial gallon?

No. A US gallon is 3.785 litres and an imperial (UK) gallon 4.546 litres, so the same tank holds fewer imperial gallons.

Should I measure the inside or outside of a container?

Use inside measurements for capacity. Outside measurements include the walls and can overestimate how much the container holds.

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