A crate 2 m by 1.5 m by 1 m
Three cubic metres, or 3 000 litres. The longest diagonal is about 2.69 m, which is what decides whether it fits through a doorway.
The surface area of 13 m² is the figure to use for wrapping, painting or insulating it.
Volume calculator
Eight solids, from a shipping box to a rounded tank, with the capacity in litres and gallons alongside the volume. Every dimension takes its own unit.
Result
Fill in the fields to see your result.
How it works
Volume is area carried through a third dimension. A box is a rectangle pushed upwards; a cylinder is a circle pushed upwards; a triangular prism is a triangle pushed sideways. In each case the rule is the same: work out the cross-section, then multiply by how far it travels.
Cones and pyramids are the exception, and share the same surprising factor. Each holds exactly a third of the box or cylinder that would enclose it, whatever the shape of the base. It is the reason a conical heap of sand looks so much smaller than the bucket it came from.
Spheres follow their own rule, four thirds of pi times the radius cubed — and the cube is what makes size so deceptive. A ball twice the diameter holds eight times as much, which is why one large scoop of ice cream beats two small ones.
Formulas used
Prisms and cylinders
V = base area × height
Cones and pyramids
V = base area × height ÷ 3
Sphere and capsule
V = 4 ÷ 3 × π r³ V = π r² L + 4 ÷ 3 × π r³
A capsule is a cylinder with a hemisphere on each end, which together make one whole sphere.
Worked examples
A cylindrical tank, 1 m across and 2 m tall
A radius of 0.5 m gives about 1.571 m³, or roughly 1 571 litres.
Widening the tank matters far more than raising it: adding 20% to the radius adds 44% to the capacity, while adding 20% to the height adds only 20%.
An aquarium in centimetres
Eighty by thirty-five by forty-five centimetres comes to 126 litres — before gravel, rocks and the gap you leave at the top.
Water weighs about a kilogram per litre, so this tank alone puts 126 kg on whatever it stands on.
Assumptions and limits
- Solids are regular and hollow-free.
- The capsule’s straight section excludes the two rounded ends.
- Pyramid and cone heights are vertical, not measured along a face.
- Capacity assumes the solid is filled completely.
Frequently asked questions
How many litres are in a cubic metre?
Exactly 1 000. The litre was defined as a cubic decimetre, and there are ten decimetres to a metre in each of three directions.
The same logic gives 1 000 cubic centimetres to a litre, which is why a millilitre and a cubic centimetre are the same thing.
Why does doubling the radius multiply the volume by eight?
Because the radius appears three times in the formula — once for each dimension. Doubling it doubles the width, the depth and the height at once, and 2 × 2 × 2 is 8.
It works in reverse too: halving a sphere’s diameter leaves it holding an eighth of what it did.
How much concrete should I order?
Work out the volume of the pour, then add for waste — usually 5 to 10% for a simple slab, more if the ground is uneven or the formwork is complicated.
Concrete is sold by the cubic metre or cubic yard, and running out halfway through a pour is far more expensive than a little surplus.
Which gallon is which?
A US gallon is 3.785 litres; an imperial gallon is 4.546 litres, about 20% larger. Both appear in the conversion table, kept separate.
Vehicle and tank specifications rarely say which they mean, so check the origin of the figure before converting it.
Updated
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