Also known as: Cubic Metre, m³, CBM Full Form, Carton CBM, Shipment Volume
CBM stands for cubic metre (m³), the unit freight forwarders use to measure shipment volume. For a carton, CBM = length × width × height in millimetres ÷ 1,000,000,000. A 600 × 400 × 400 mm carton is 0.096 CBM. Sea LCL freight is charged on weight or measure: 1 CBM is treated as 1,000 kg, and you pay on whichever is greater.
The formula is straightforward but the units trip people up. Measure the outside of the packed carton — length, width and height — in millimetres, multiply them and divide by 1,000,000,000 to get cubic metres. In centimetres, divide by 1,000,000. A 600 × 400 × 400 mm carton is 0.6 × 0.4 × 0.4 = 0.096 m³, so 100 of them make 9.6 CBM. Always use the external size, including bulging flaps or straps, because that is what the forwarder measures. One cubic metre is about 35.3 cubic feet, if a buyer quotes in CFT.
In sea freight, less-than-container-load (LCL) cargo is billed on weight or measure, written W/M. One revenue ton equals 1 CBM or 1,000 kg, whichever is greater. If the 100 cartons above weigh 12 kg each, the shipment is 9.6 CBM and 1.2 tonnes, so it is charged as 9.6 revenue tons — on volume. Fifty cartons of steel fasteners at 300 × 200 × 200 mm and 30 kg each are 0.6 CBM and 1.5 tonnes, so they are charged as 1.5 revenue tons — on weight. Almost all cushioned packaging is charged on volume.
Air and courier freight convert volume differently. They use a volumetric divisor: at the IATA air cargo convention of 6000, one cubic metre is charged as about 167 kg; at the 5000 divisor used by most Indian express and e-commerce carriers it is charged as 200 kg. That is why a light, bulky foam-packed product costs far more by air than its weight suggests, and why the volumetric weight calculator is worth running before a pack is approved.
For full container loads, CBM tells you how much will fit. Hapag-Lloyd lists the capacity of a 20 ft standard container at 33.2 m³, a 40 ft standard at 67.7 m³ and a 40 ft high cube at 76.3 m³. Usable volume is lower, because cartons rarely fill the width and height exactly and pallets, dunnage and door clearance take space; pallet counts per container are a better planning figure than raw CBM for palletised cargo.
Packaging decides CBM more than the product does. Taking 20 mm off each dimension of the 600 × 400 × 400 mm carton gives 580 × 380 × 380 mm, or 0.0838 CBM — about 13% less volume on every LCL shipment. A die-cut foam fitment that locates the product precisely usually allows a tighter carton than loose fill, and right-sizing the corrugated outer is the cheapest freight saving most exporters from Rajkot to Mundra or Nhava Sheva can make. Cut too far, though, and the cushion runs out: check the foam thickness against the cushion curve before shrinking the box.
CBM (Cubic Metre) at a glance
| Full form | Cubic metre (m³) |
|---|---|
| Formula (mm) | L × W × H ÷ 1,000,000,000 |
| Formula (cm) | L × W × H ÷ 1,000,000 |
| Example | 600 × 400 × 400 mm = 0.096 CBM |
| Sea LCL billing | W/M: 1 revenue ton = 1 CBM or 1,000 kg, whichever is greater |
| Air (IATA 6000) | 1 CBM ≈ 167 kg chargeable |
| Container capacity (Hapag-Lloyd) | 20 ft 33.2 m³; 40 ft 67.7 m³; 40 ft HC 76.3 m³ |
| Conversion | 1 m³ ≈ 35.3 ft³ |
Common questions
How do I calculate CBM of a carton?
Multiply the external length, width and height in millimetres and divide by 1,000,000,000. A 600 × 400 × 400 mm carton is 96,000,000 ÷ 1,000,000,000 = 0.096 CBM. Multiply by the number of cartons for the shipment total.
How many kg is 1 CBM in sea freight?
For LCL sea freight, 1 CBM is treated as equal to 1,000 kg. The shipment is charged in revenue tons on whichever is greater: its volume in CBM or its weight in tonnes. Light, bulky cargo is billed on CBM; dense cargo such as metal parts is billed on weight.
How many CBM fit in a 20 ft container?
Hapag-Lloyd lists a 20 ft standard container at 33.2 m³ internal capacity, a 40 ft standard at 67.7 m³ and a 40 ft high cube at 76.3 m³. The volume you can actually load is lower once carton fit, pallets and dunnage are allowed for.
What is the difference between CBM and volumetric weight?
CBM is the physical volume of the shipment. Volumetric weight converts that volume into a chargeable weight using a carrier divisor, such as 6000 for air cargo or 5000 for most Indian couriers. Sea LCL uses CBM directly at 1 CBM to 1,000 kg.
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