CBM = cubic metre
Container CBM Guide
CBM (“cubic metre”) is how ocean freight measures cargo volume: length × width × height in metres, times quantity. A carton of 60 × 40 × 40 cm is 0.096 CBM; a hundred of them are 9.6 CBM.
Containers are quoted in geometric capacity: 33.2 CBM for a 20 ft, 67.7 for a 40 ft, 76.4 for a 40 ft high cube, 86 for a 45 ft. Real-world stuffing reaches 80–90% of that — cartons never tile a box perfectly.
Practical loading capacity
Plan on roughly 26–28 CBM usable in a 20 ft, 55–60 CBM in a 40 ft and 65–68 CBM in a 40 ft HC for mixed cartons. Uniform carton sizes, cargo that tolerates rotation and minimal palletising push the number up; fragile or odd-shaped goods pull it down.
Use our CBM calculator to convert your carton dimensions and count into cubic metres and see the fill percentage per container size.
CBM vs weight: which limit bites first
Every container runs out of either space or weight. Divide payload by capacity: a 20 ft gives ~850 kg per CBM, a 40 ft HC ~375 kg per CBM. If your cargo is denser than that, weight is your constraint and volume goes unused — a key reason heavy cargo moves in 20 ft boxes.
Frequently asked questions
How many CBM is a 40 ft container?
Geometric capacity is 67.7 CBM (76.4 for the high cube). Practically loadable volume for mixed cartons is about 55–60 CBM (65–68 for the HC).
How do I calculate CBM?
Multiply length × width × height of one package in metres, then by the number of packages. Example: 0.6 × 0.4 × 0.4 m × 250 pcs = 24 CBM.
How many CBM fit in a 20 ft container?
33.2 CBM geometric; plan for 26–28 CBM of real cargo.