10 minute practical guide
How to Calculate CBM for Shipping: Formula & Examples
Calculate shipping CBM from centimetres, metres or inches for one or multiple carton sizes and avoid common conversion errors.
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Total every carton group at once
Add each carton size with its quantity and weight in mm, cm, m or inches, get the shipment total volume and gross weight, and export an auditable CSV calculation.
Calculate CBMCBM calculation in brief
Multiply length × width × height after converting all dimensions to metres, then multiply by quantity. For centimetres, use (L × W × H × quantity) ÷ 1,000,000. Calculate each carton size separately and add the results.
CBM formula
For dimensions in metres, CBM = length × width × height × quantity. CBM measures shipment volume; it is not the same as gross weight, chargeable weight or guaranteed container loadability.
| Input unit | Conversion | Example | Result |
|---|---|---|---|
| Metres | L × W × H | 1.2 × 0.8 × 1.0 m | 0.960 CBM |
| Centimetres | ÷ 1,000,000 | 120 × 80 × 100 cm | 0.960 CBM |
| Millimetres | ÷ 1,000,000,000 | 1200 × 800 × 1000 mm | 0.960 CBM |
| Inches | × 0.000016387064 | 47.24 × 31.50 × 39.37 in | 0.960 CBM |
| Feet | × 0.028316846592 | 3.94 × 2.62 × 3.28 ft | 0.960 CBM |
The same box in five units. If your five answers differ, a conversion is wrong — this is the fastest way to find it.
Calculate CBM from centimetres
For cartons measured in centimetres, multiply length, width, height and quantity, then divide by 1,000,000. Example: 50 cartons measuring 60 × 40 × 40 cm occupy 4.8 CBM.
The division by a million is the step people drop when working quickly, and the resulting answer is wrong by six orders of magnitude — which at least makes it obvious.
Calculate CBM from inches
For inches, multiply cubic inches by 0.000016387064, then multiply by quantity. Keep all three dimensions in the same unit before converting.
Multiple-carton worked example
Calculate each size group separately. If 20 cartons occupy 1.2 CBM and another 10 cartons occupy 0.8 CBM, the shipment total is 2.0 CBM. Do not average different carton dimensions because averaging changes the calculated volume.
Averaging 60 × 40 × 50 and 80 × 60 × 40 to 70 × 50 × 45 and multiplying by thirty cartons gives 4.725 CBM against a true 4.320 — nearly ten per cent high, and impossible to reconcile when the consolidator measures the cargo.
CBM and volumetric weight
Airlines and couriers may convert volume to a volumetric weight using a contracted divisor, then compare it with actual weight. Ocean LCL commonly uses a weight-or-measure basis. Use the applicable chargeable-weight or LCL calculator rather than treating CBM as kilograms.
| Basis | Divisor | 1 CBM equals |
|---|---|---|
| General air cargo | 6,000 cm³/kg | 167 kg |
| International express | 5,000 cm³/kg | 200 kg |
| European road groupage | 3,000 cm³/kg | 333 kg |
| Ocean LCL, weight or measure | — | 1,000 kg |
The same cubic metre of the same cargo, priced four different ways. There is no universal CBM-to-kilogram conversion.
CBM and container capacity
A container’s nominal cubic capacity is higher than practical usable space. Door clearance, carton orientation, pallets, dunnage, load distribution, payload and safe handling reduce what can be loaded. Use a carton-fit estimate as planning guidance, not a stowage guarantee.
Plan on 80 to 85 per cent of nominal capacity for floor-loaded cartons, and less again for palletised cargo where the pallet consumes height on every layer.
Common CBM mistakes
The most common errors are mixing units, forgetting quantity, averaging unlike cartons, rounding each row too early, and assuming total CBM guarantees physical fit. Preserve precision until the final total and confirm the carrier’s measurement and rounding rules.
One more worth naming: measuring the flat carton specification rather than the packed article. Cartons packed tight bulge, and the consolidator measures what arrives, not what was specified.
Put the guide into practice
Add each carton size with its quantity and weight in mm, cm, m or inches, get the shipment total volume and gross weight, and export an auditable CSV calculation.
Calculate CBMFrequently asked questions
Direct answers to the questions this topic raises most often in day-to-day operations.
What is the CBM formula?
CBM = length × width × height × quantity, with all dimensions in metres. From centimetres, multiply the three dimensions and the quantity then divide by 1,000,000. From inches, multiply cubic inches by 0.000016387064. Calculate each carton size separately and add the group totals.
How many kg is 1 CBM?
It depends entirely on the pricing basis. Ocean LCL treats 1 CBM as 1,000 kg. General air cargo treats it as 167 kg at the 6,000 divisor, express couriers as 200 kg at 5,000, and European road groupage as 333 kg. There is no universal conversion — always state which basis you mean.
Should I use internal or external carton dimensions?
External, always. The carrier, consolidator or handling agent measures the outside of the package as presented, including bulge from tight packing, banding and protruding features. Internal dimensions describe what fits inside the box and are irrelevant to freight measurement.
How do I calculate CBM for pallets?
Measure the loaded pallet as one unit: footprint length × footprint width × total height including the pallet. A 1.20 × 0.80 m EUR pallet loaded to 1.55 m overall is 1.488 CBM. Do not sum the cartons and ignore the pallet — you will understate by 10 to 20 per cent.
Can I average carton sizes to save time?
No. Averaging unlike dimensions changes the calculated volume, usually upward, and produces a figure that cannot be reconciled against the packing list. Calculate each group and add the results.
Does CBM tell me if my cargo fits in a container?
It tells you whether it might. Nominal capacity assumes a perfect rectangular fill that no real load achieves. Plan on 80 to 85 per cent for floor-loaded cartons and less for palletised cargo, then confirm the payload limit separately — dense cargo runs out of weight before space.
Why is the consolidator's CBM higher than mine?
Because they measure the cargo as it arrives, to the outermost point: pallets add height, shrink wrap adds width, overhang counts, and tightly packed cartons bulge beyond their printed dimensions. A 10 to 20 per cent difference on palletised cargo is normal; a larger gap is worth querying.
How many decimal places should CBM have?
Carry full precision through the calculation and round once at the end, conventionally to three decimal places. Rounding each row first pushes the error consistently in one direction across a long packing list.
What is the difference between CBM and volumetric weight?
CBM measures space. Volumetric weight is a billing figure derived from that space by dividing by a contractual divisor, so light bulky cargo pays for the room it occupies. One CBM is always one CBM; its volumetric weight depends on whose tariff you are under.
Does CBM include the pallet?
For freight measurement, yes — the pallet is part of the article presented for carriage and the carrier measures the loaded unit. For a packing list describing what is inside the shipment you may show carton volume separately, but the freight figure is the loaded pallet.