CBM Calculator
Convert carton dimensions into cubic metres (CBM) for ocean and air freight, with chargeable weight and container fit.
What is CBM (cubic metre)?
CBM is the volume of your cargo in cubic metres, the basis for ocean LCL and air freight pricing. Convert each dimension to metres and multiply: CBM = (L × W × H) in metres. A 40 × 30 × 25 cm carton is 0.40 × 0.30 × 0.25 = 0.03 CBM. Multiply by the carton count for the shipment total. Ocean LCL is charged on a weight-or-measure (W/M) basis — whichever is greater, one tonne or one CBM. Air freight uses a volumetric weight of about 167 kg per CBM.
Container Capacity Reference
| Container | Internal CBM | Usable CBM |
|---|---|---|
| 20ft standard | 33 m³ | ~28 m³ |
| 40ft standard | 67 m³ | ~58 m³ |
| 40ft high cube | 76 m³ | ~68 m³ |
| Air (per CBM) | — | 167 kg vol. |
Frequently Asked Questions
How do I calculate CBM?
Convert length, width and height to metres and multiply. A 40 × 30 × 25 cm carton is 0.40 × 0.30 × 0.25 = 0.03 CBM. For 100 cartons that is 3.0 CBM total.
What is chargeable weight for ocean LCL?
Ocean LCL uses weight-or-measure (W/M): you are charged for whichever is greater — one revenue tonne (1000 kg) or one cubic metre. Enter the weight per carton and the calculator shows both so you can see which governs.
How is air freight volumetric weight found?
Air freight charges the greater of the actual weight and a volumetric weight of about 167 kg per cubic metre (the IATA 1:6000 rule). 3 CBM equals roughly 500 kg of volumetric weight.
How many cartons fit in a container?
Divide the usable container volume by your carton CBM: about 28 m³ for a 20ft and 58 m³ for a 40ft in practice. Real loading is a little less because cartons never tessellate perfectly — use the Pallet or Carton calculator for an exact layout.
Should I use inner or outer carton size?
Always the outer size. Freight is charged on the space the carton occupies, so board thickness and any bulge count toward the CBM.