Quick answer: m³ = length × width × height, all in metres. Measured in centimetres? Multiply the three sides and divide by 1,000,000. One cubic metre holds 1,000 litres and equals 35.31 cubic feet.
How to calculate cubic metres
A cubic metre is the space inside a cube one metre on each side. Every volume in cubic metres comes from three lengths in metres multiplied together, so the first step is always to get each side into metres.
- Measure the length, width and height. A carton measures 120 cm × 80 cm × 60 cm.
- Convert to metres by dividing each centimetre figure by 100: 1.2 m × 0.8 m × 0.6 m.
- Multiply: 1.2 × 0.8 × 0.6 = 0.576 m³, which is 576 litres.
Converting after multiplying works too, but the divisor grows with the cube. Centimetres need 100³ = 1,000,000, and millimetres need 1,000³ = 1,000,000,000. Dividing by 100 once instead of a million times is the most common cubic metre mistake.
For a round tank or pipe, use the cylinder shape: π × radius² × height. A water tank 1.5 m across and 2 m tall holds π × 0.75² × 2 = 3.53 m³, or 3,534 litres.
Cubic metre conversion chart
| 1 cubic metre equals | Value | To convert back to m³ |
|---|---|---|
| Litres | 1,000 | ÷ 1,000 |
| Cubic centimetres (cm³) | 1,000,000 | ÷ 1,000,000 |
| Cubic feet (ft³) | 35.315 | × 0.028317 |
| Cubic yards (yd³) | 1.308 | × 0.76455 |
| Cubic inches (in³) | 61,023.7 | ÷ 61,023.7 |
| US gallons | 264.17 | × 0.0037854 |
| UK (imperial) gallons | 219.97 | × 0.0045461 |
The volume conversion calculator converts between any of these units directly, and the litres volume calculator works in litres from the start.
What a cubic metre looks like
| Item | Cubic metres |
|---|---|
| Bathtub filled for a bath | ≈ 0.15 |
| Fridge-freezer, outside size 0.6 × 0.65 × 1.8 m | 0.70 |
| Euro pallet stacked 1.5 m high (1.2 × 0.8 m) | 1.44 |
| Bedroom 4 × 3 m with a 2.5 m ceiling | 30 |
| 20 ft shipping container (internal) | ≈ 33 |
| 40 ft shipping container (internal) | ≈ 67 |
| Olympic swimming pool (50 × 25 × 2 m) | 2,500 |
Weight follows from density. A cubic metre of water weighs about 1,000 kg, while a cubic metre of concrete weighs about 2,400 kg. The water weight calculator and the volume to weight calculator convert a volume into a mass for other materials.
Where cubic metres decide the price
- Shipping (CBM). Sea freight and consolidated cargo are priced per cubic metre. Multiply one carton's volume by the carton count, then check it against container capacity in the freight volume calculator.
- Concrete and aggregates. Ready-mix suppliers outside the US sell concrete by the cubic metre. The concrete volume calculator adds a waste allowance for slabs, footings and columns.
- Water bills and tanks. Water meters in most countries read in cubic metres, and one unit on the bill is 1,000 litres.
- Rooms and ventilation. Air-change and heating calculations start from room volume in m³. The room volume calculator handles L-shaped rooms and sloped ceilings.
- US projects. Builders in the US order by the cubic yard and ship by the cubic foot. Use the cubic yard calculator or the cubic feet calculator for quotes in those units.
Frequently asked questions
How do I calculate cubic metres?
Multiply length × width × height with all three in metres. A box 1.2 m long, 0.8 m wide and 0.6 m high holds 1.2 × 0.8 × 0.6 = 0.576 m³. The calculator above converts centimetres, millimetres, feet and inches for you, so you can enter each side in the unit you measured it in.
How do I convert centimetres to cubic metres?
Multiply the three sides in centimetres and divide by 1,000,000, because a cubic metre is 100 × 100 × 100 cm. A carton 120 × 80 × 60 cm is 576,000 cm³, which is 0.576 m³. For millimetres, divide the product by 1,000,000,000.
How many litres are in a cubic metre?
One cubic metre holds exactly 1,000 litres. A litre is one cubic decimetre, and a cubic metre is 10 × 10 × 10 decimetres. The same cubic metre is 264.2 US gallons or 220.0 UK gallons.
How many cubic feet are in a cubic metre?
One cubic metre is 35.31 cubic feet, because a metre is 3.2808 feet and 3.2808³ = 35.31. To go the other way, multiply cubic feet by 0.02832. A 500 ft³ load is about 14.16 m³.
How much does a cubic metre of water weigh?
A cubic metre of fresh water weighs about 1,000 kg, one metric tonne. The exact figure is 999.97 kg at 4 °C and about 998.2 kg at 20 °C, because water expands slightly as it warms. Seawater is heavier, at roughly 1,025 kg per cubic metre.
What is CBM in shipping?
CBM stands for cubic metre, the unit freight forwarders use to price sea and air cargo by space. Multiply carton length × width × height in metres, then multiply by the number of cartons. The freight volume calculator adds chargeable weight and container fill.