Key points
- CBM = length × width × height in metres × number of cartons.
- From centimetres divide by 1,000,000; from millimetres by 1,000,000,000; 1 CBM = 35.31 cubic feet.
- Measure the outer carton at its widest points; small errors add up over hundreds of cartons.
- Sea LCL is charged by W/M: CBM or tonnes, whichever is greater, usually with a 1 CBM minimum.
- Container capacity depends on how cartons fit the inside dimensions, not only on total CBM.
The CBM formula
CBM means cubic metre, the volume of a box 1 m long, 1 m wide and 1 m high. For one carton, CBM = length × width × height, with all three in metres. For a shipment, multiply by the number of cartons and add up the lines of your packing list. Most Chinese suppliers measure in centimetres, so multiply the three sides in centimetres and divide by 1,000,000. If the sizes are in millimetres, divide by 1,000,000,000. For inches, multiply the three sides and divide by 61,024, because one cubic metre is about 61,024 cubic inches. If you already have cubic feet, multiply by 0.0283 or divide by 35.31.
Usable space: 20GP ~25–28 CBM, 40GP ~55–58, 40HQ ~65–68.
Worked examples
- Measure one cartonMeasure the outer carton: 60 cm long, 40 cm wide, 50 cm high.
- Convert to metres60 cm = 0.60 m, 40 cm = 0.40 m, 50 cm = 0.50 m.
- Multiply the three sides0.60 × 0.40 × 0.50 = 0.12 CBM per carton.
- Multiply by quantity50 cartons × 0.12 CBM = 6.00 CBM.
- Add every lineRepeat for each carton size on the packing list and add the results.
- Check against weightTotal the gross weight too, because LCL charges whichever is greater, CBM or tonnes.
| Package | Size | CBM each | Quantity | Total CBM |
|---|---|---|---|---|
| Carton | 60 × 40 × 50 cm | 0.120 | 50 | 6.00 |
| Carton | 45 × 35 × 30 cm | 0.047 | 200 | 9.45 |
| Pallet, loaded | 120 × 100 × 150 cm | 1.800 | 4 | 7.20 |
| Pallet, loaded | 1,200 × 800 × 1,000 mm | 0.960 | 10 | 9.60 |
| Carton | 24 × 18 × 12 in | 0.085 | 100 | 8.50 |
Note the second row: 0.04725 CBM per carton, shown rounded as 0.047. Multiply with the unrounded figure (0.04725 × 200 = 9.45 CBM); multiplying the rounded figure gives 9.40, a small but avoidable difference. For pallets, measure the loaded pallet including the wooden base and any overhang, not the cartons alone.
Rounding and measuring rules
- Measure the outside of the carton at its widest points, including bulges, straps and handles.
- Measure a few cartons of each size; filled cartons are often larger than the size printed on them.
- Keep at least three or four decimals per carton and round only the shipment total, usually to two decimals.
- For pallets, measure the full loaded pallet from the floor to the highest point.
- Use the same unit for all three sides before multiplying.
- The consolidator's warehouse measures LCL cargo on arrival, and its figure is normally the one you are billed on. Ask how it rounds.
From CBM to W/M: how LCL is charged
Sea LCL is priced per W/M, short for weight or measure. The consolidator compares your volume in CBM with your gross weight in tonnes, using 1 CBM = 1,000 kg, and charges whichever is greater. Light cargo pays by volume and dense cargo pays by weight. A minimum, commonly 1 CBM, applies to small lots, and CFS fees at origin and destination are often charged per W/M as well. Air freight uses a very different ratio, 1 CBM = 167 kg, so the same CBM can give a much higher chargeable weight by air.
Usable space: 20GP ~25–28 CBM, 40GP ~55–58, 40HQ ~65–68.
| Shipment | Volume | Weight | Charged as |
|---|---|---|---|
| Garments | 6 CBM | 2,000 kg (2 t) | 6 W/M, by volume |
| Machine parts | 3 CBM | 4,500 kg (4.5 t) | 4.5 W/M, by weight |
| Samples | 0.6 CBM | 300 kg (0.3 t) | 1 W/M, the minimum |
| Furniture | 11.4 CBM | 1,900 kg (1.9 t) | 11.4 W/M, by volume |
How many cartons fit in a container
Dividing the usable volume by the CBM per carton gives a first estimate, but the real answer depends on how many whole cartons fit along each inside dimension. Take the 60 × 40 × 50 cm carton (0.12 CBM). A 20GP is about 590 × 235 × 239 cm inside. Stacked one way, 9 cartons fit along the length, 5 across and 4 high: 180 cartons, or 21.6 CBM, below the 25–28 CBM a 20GP usually takes, because 39 cm of height is left empty. In a 40HQ (about 1,203 × 235 × 269 cm) the same carton fits 20 × 5 × 5 = 500 cartons, or 60.0 CBM. The loader can sometimes fit more by turning part of the load, but a simple stacking calculation shows the safe number.
| Container | Inside L × W × H (cm) | Cartons that fit (60 × 40 × 50 cm) | Loaded CBM | Typical usable CBM |
|---|---|---|---|---|
| 20GP | 590 × 235 × 239 | 180 (9 × 5 × 4) | 21.6 | 25–28 |
| 40GP | 1,203 × 235 × 239 | 400 (20 × 5 × 4) | 48.0 | 55–58 |
| 40HQ | 1,203 × 235 × 269 | 500 (20 × 5 × 5) | 60.0 | 65–68 |
Check your figures before booking
CBM checklist
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Frequently asked questions
How do I calculate CBM in cm?
Multiply length × width × height in centimetres and divide by 1,000,000. For example, 60 × 40 × 50 cm = 120,000 ÷ 1,000,000 = 0.12 CBM.
How do I calculate CBM from inches?
Multiply the three sides in inches and divide by 61,024. A 24 × 18 × 12 in carton is about 0.085 CBM.
How many cubic feet are in one CBM?
About 35.31 cubic feet. To convert cubic feet to CBM, multiply by 0.0283.
What is W/M in shipping?
Weight or measure: for sea LCL the carrier compares CBM with gross weight in tonnes (1 CBM = 1,000 kg) and charges the greater figure.
How many CBM fit in a 20ft container?
About 33 CBM nominal, but usually 25–28 CBM of cartons in practice, depending on carton sizes.
Is there a minimum CBM for LCL?
Yes, most consolidators charge at least 1 CBM (1 W/M) per shipment, plus fixed fees.
Whose CBM figure is used for billing?
For LCL, normally the figure measured at the consolidator's warehouse when the cargo arrives, which is why accurate packing lists matter.
Sources
General information checked on the date shown. Rules and rates change: our team confirms the details for your shipment.