CBM, or cubic metre volume, is one of the most common space measurements used in freight and cargo planning. It tells you how much three-dimensional space a shipment occupies before weight limits, palletization and loading restrictions are considered.
The basic CBM formula
For a rectangular package, convert the outside packed dimensions to metres and multiply length × width × height. If every carton is the same size, multiply that volume by the number of cartons.
CBM = length (m) × width (m) × height (m) × quantity
For example, a carton measuring 60 cm × 40 cm × 35 cm converts to 0.60 × 0.40 × 0.35 metres. One carton is 0.084 m³. Ten identical cartons total 0.84 m³.
Use the CBM Calculator when you want the metric and cubic-foot result without doing the unit conversion manually.
Use packed outside dimensions
Measure the shipment as it will actually be handed to the carrier. Protective corners, outer cartons, crates, wrapping and bulges can increase the real space used. Product dimensions from a catalogue are often smaller than transport dimensions.
Mixed carton sizes
If a shipment has several carton sizes, calculate each size group separately and add the CBM totals. Do not average the dimensions unless the packages are genuinely uniform.
CBM does not guarantee physical fit
A container or vehicle has a theoretical internal cubic volume, but cargo cannot normally use every cubic centimetre. Door openings, pallet footprints, orientation, dunnage, load securing and unusable gaps all affect physical fit. For a simple carton count estimate, use the Container Loading Calculator.
Common CBM mistakes
- Mixing centimetres and metres in the same formula.
- Forgetting to multiply by quantity.
- Using product dimensions instead of packed dimensions.
- Rounding each carton too aggressively before multiplying a large quantity.
- Assuming CBM alone determines freight price or container capacity.
CBM is a strong first planning number because it makes shipment size comparable across cartons, pallets and container types. Keep the underlying dimensions available so the result can be checked later.