Quick answer: CBM = length × width × height (metres) × number of cartons. A 60 × 40 × 40 cm carton is 0.096 CBM, so 100 of them is 9.6 CBM. From centimetres, divide the product by 1,000,000.
Container capacity
| Container | Internal CBM | Practical load | Max payload |
|---|---|---|---|
| 20 ft standard | 33.2 | 25–28 CBM | ≈ 28,000 kg |
| 40 ft standard | 67.7 | 55–58 CBM | ≈ 26,700 kg |
| 40 ft high cube | 76.4 | 65–68 CBM | ≈ 26,500 kg |
| 45 ft high cube | 86.1 | 72–78 CBM | ≈ 27,700 kg |
Note that a 40-foot container carries roughly twice the volume of a 20-foot but barely any more weight. That is why dense cargo — tiles, machinery, liquids — often "weighs out" in a 20-foot while light cargo "cubes out" in a 40. Which limit you hit first determines which container is economical.
Chargeable weight: air versus ocean
Ocean LCL: 1 CBM = 1,000 kg (1 revenue ton)
Chargeable = the greater of actual and volumetric
Worked example — 100 cartons at 60 × 40 × 40 cm, 8 kg each:
- Volume: 0.096 CBM × 100 = 9.6 CBM
- Actual weight: 8 × 100 = 800 kg
- Air volumetric: 9.6 × 167 = 1,603 kg → billed on 1,603 kg
- Ocean LCL: 9.6 CBM against 0.8 tonnes → billed on 9.6 revenue tons
The density that decides it: below 167 kg per CBM for air, your shipment is billed on volume. This one weighs 83 kg per CBM, so volume wins comfortably — which is typical of consumer goods and packaging-heavy cargo.
LCL or a full container?
Less-than-container-load means sharing a container with other shippers, priced per CBM. Full container load means booking the whole box at a flat rate. The crossover typically falls around 13–15 CBM, but it moves with lane, season and rate volatility.
Volume is not the only consideration. FCL usually moves faster because it skips consolidation and deconsolidation at both ends, and it lowers handling damage risk because the container is sealed at origin. If you are near the crossover, price both — and remember that a 20-foot container practically loading 25–28 CBM still costs a flat rate whether you fill it or not.
Common mistakes & pro tips
- Measuring cartons when shipping palletised. Pallet footprint and total stacked height is what occupies container space — including the pallet's own 15 cm.
- Using internal container volume as loadable. Theoretical CBM is never achievable. Use the practical figures above.
- Forgetting the air freight ratio. At 167 kg per CBM, most consumer goods bill on volume, not mass.
- Mixing units. CBM needs metres. From centimetres, divide by 1,000,000; from inches, by 61,024.
- Pro tip — optimise carton size to the pallet. A carton that tessellates neatly on a 120 × 100 cm pallet wastes far less paid space than one that leaves gaps on every layer.
- Pro tip — check both limits. Calculate volume and weight against the container's payload. Dense cargo hits the weight limit long before the box is full.
Frequently asked questions
How do I calculate CBM for shipping?
Multiply length × width × height in metres for one carton, then multiply by the number of cartons. A carton measuring 60 × 40 × 40 cm is 0.6 × 0.4 × 0.4 = 0.096 CBM, so 100 of them is 9.6 CBM. If you measure in centimetres, divide the product by 1,000,000.
How many CBM fit in a shipping container?
A 20-foot container has about 33 CBM of internal space but realistically loads 25 to 28 CBM. A 40-foot holds about 67 CBM with a practical limit near 55 to 58, and a 40-foot high cube about 76 CBM loading 65 to 68. The gap between theoretical and practical is packing inefficiency, and forwarders quote against the practical figure.
What is chargeable weight in freight?
The greater of actual weight and volumetric weight. Air freight commonly uses 1 CBM = 167 kg, so a 10 CBM shipment weighing 1,000 kg is charged at 1,670 kg. Ocean LCL typically uses 1 CBM = 1,000 kg, meaning the same shipment would be charged on 10 revenue tons.
When should I switch from LCL to a full container?
Usually somewhere around 13 to 15 CBM, though it depends on the lane and season. Below that, less-than-container-load shared shipping is cheaper; above it, a full 20-foot container often costs less in total and moves faster because it skips consolidation and deconsolidation.
Should I measure cartons or pallets?
Pallets, if the goods will ship palletised. A pallet's footprint and total stacked height including the pallet itself is what occupies container space, and the voids between cartons on the pallet are space you pay for. Measuring loose cartons will understate a palletised shipment.