Construction & trade New Zealand
Cubic Meter Calculator
Enter three dimensions in whatever unit you measured in. The result comes back in cubic metres, litres and cubic feet, with an estimated weight for the material you are actually moving.
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Volume
—Litres
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Cubic feet
—
Per item
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Estimated weight
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How do you calculate cubic metres?
Multiply length by width by height, with all three in metres. A box 2 m long, 1.5 m wide and 1.2 m high is 2 × 1.5 × 1.2 = 3.6 cubic metres. If you measured in millimetres, divide each dimension by 1,000 first — or divide the final answer by a billion, which is the same thing done later.
Where cubic metres actually get used
The same number does very different jobs depending on who is asking for it.
For landscaping supplies — soil, bark, aggregate, sand — cubic metres are how the yard sells it, and the figure you want is the volume of the space you need to fill.
For freight and moving, the cubic figure sets the space your consignment occupies, and carriers price on it whenever the goods are light for their size.
For concrete and fill it is a purchase quantity, usually with a waste allowance added before ordering.
In all three cases the underlying arithmetic is identical. What changes is whether you add an allowance on top, and how much.
Volume against weight
A cubic metre is a fixed volume and a wildly variable weight. Bark mulch runs around 350 kilograms per cubic metre; concrete is close to 2,400. That is nearly a sevenfold difference for the same space.
This matters for anything involving a trailer, a ute or a suspended floor. A cubic metre of mulch is comfortable in a small trailer. A cubic metre of wet sand is over 1.6 tonnes and beyond what most domestic trailers are rated for, regardless of whether it physically fits.
The densities in the material list are typical figures for estimating. Moisture content moves them significantly — wet sand can be 20 per cent heavier than dry.
How this is calculated
Volume is three dimensions multiplied together, once they are all in the same unit.
V (m³) = length × width × height, all in metresfrom millimetres: divide each by 1,000 (or the answer by 1,000,000,000)from centimetres: divide each by 100 (or the answer by 1,000,000)1 m³ = 1,000 litres = 35.3147 cubic feetweight (t) = V × density (t/m³)
The unit conversion is where this goes wrong, and it goes wrong by a factor of a billion rather than a thousand — because the conversion applies three times, once per dimension.
A box measured as 2,000 × 1,500 × 1,200 millimetres is 3,600,000,000 cubic millimetres, which is 3.6 cubic metres. Dividing by 1,000 instead of 1,000,000,000 gives 3,600,000, which is obviously wrong and still gets typed into freight quotes.
A worked example: a freight consignment
Four crates, each measuring 2,000 × 1,500 × 1,200 millimetres. What is the total cubic volume?
- Convert each dimension to metres2 × 1.5 × 1.2 m
- Volume of one crate3.6 m³
- Four crates14.4 m³
- In litres14,400 L
- In cubic feet508.5 ft³
14.4 cubic metres in total, or 3.6 m³ per crate.
Freight is usually charged on whichever is greater, actual weight or volumetric weight. For light bulky goods the cubic figure is the one that sets the price, which is why it is worth calculating before booking rather than after.
What this calculator does not do
- Assumes a rectangular shape; irregular volumes need breaking into parts
- Material densities are typical values and vary with moisture and compaction
- Does not add a waste or settling allowance — that belongs to the specific job
- Freight volumetric weight rules vary by carrier and are not applied here
Common questions
How do you work out cubic metres?
Multiply length by width by height with all three in metres. If you measured in millimetres, convert each dimension first — dividing the final answer by 1,000 is the classic mistake, because the conversion applies three times.
How many litres are in a cubic metre?
Exactly 1,000. It is one of the cleanest conversions in the metric system, and a cubic metre of water weighs exactly one tonne.
How many cubic metres fit in a trailer?
A standard 6 × 4 box trailer holds roughly one cubic metre heaped, or about 0.7 level. Weight is usually the real limit though — a cubic metre of sand is well over a tonne.
What is volumetric weight in freight?
A carrier's way of charging for space rather than mass, applied when goods are light for their size. Each carrier uses its own conversion factor, so check theirs rather than assuming a standard one.
Is a cubic metre the same as a cube metre or m3?
Yes — cubic metre, cubic meter, m³ and m3 all mean the same volume. The spelling difference is just British against American convention.
Where these numbers come from
- Wolfram MathWorld — volume of a cuboid Fixed formula; material densities are typical estimating values
Method last reviewed 2026-10-28 This calculator uses fixed rules rather than rates that change, and its method is re-checked against the sources above at least once a year. Out of date? Tell us and we will fix it.
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