How to Calculate CBM for Shipping
Last updated: 2026-08-11
CBM is the unit that decides LCL pricing, container fit and often the chargeable weight of your shipment. The formula is trivial; the mistakes are in the units, the packaging allowance and the difference between volume and chargeable weight.
The CBM formula
CBM = length (m) × width (m) × height (m), using outer carton dimensions including packaging.
Example: a carton of 60 × 40 × 30 cm = 0.6 × 0.4 × 0.3 = 0.072 CBM. For 250 cartons: 18 CBM.
If your dimensions are in centimetres, divide the product by 1,000,000. In inches, divide by 61,024.
CBM vs volumetric weight
| Mode | Chargeable basis | Rule of thumb |
|---|---|---|
| Sea LCL | Greater of CBM or metric tonnes (w/m) | 1 CBM ≈ 1,000 kg equivalence |
| Air freight | Greater of actual or volumetric kg | Volumetric kg = cm³ / 6,000 (typical) |
| Courier | Greater of actual or volumetric kg | Divisor often 5,000 |
Dense cargo (metal, chemicals in drums) usually charges on weight; light cargo (packaging, foam, plastics) charges on volume.
CBM for pallets
Pallet CBM uses the loaded height including the pallet itself. A Euro pallet (0.8 × 1.2 m) loaded to 1.5 m total height is 0.8 × 1.2 × 1.5 = 1.44 CBM. Always include the pallet deck height — forgetting it understates every shipment.
How much fits in a container
| Container | Nominal capacity | Realistic loadable |
|---|---|---|
| 20ft dry | ~33 CBM | ~25–28 CBM |
| 40ft dry | ~67 CBM | ~54–58 CBM |
| 40ft high cube | ~76 CBM | ~60–65 CBM |
The gap between nominal and realistic is stacking loss, pallet overhang and unusable corner space. Model your actual cartons in the Container Loading module or the Pallet Calculator.
Open the Tradloc module and run your own numbers.
Boxes per pallet and pallets per container.
Fit cartons into 20ft / 40ft / 40HC.
Related guides
Frequently Asked Questions
- How do I convert cm to CBM?
- Multiply length × width × height in centimetres and divide by 1,000,000.
- How many cartons fit in a 40ft container?
- Divide realistic loadable volume (~54–58 CBM) by carton CBM, then reduce for stacking and pallet losses. Model your exact carton size for a reliable answer.
- Should I use inner or outer carton dimensions?
- Always outer dimensions, including packaging and any protrusions — that is what occupies space on the vessel.