What Is CBM in Shipping? (Cubic Meter Meaning & Formula)
CBM is the single most important number in an LCL freight quote. Here is what it means, how to calculate it, and how it turns into the price you pay.
CBM means cubic meter (m³) — the volume your shipment occupies. You calculate it as length × width × height in meters, multiplied by the quantity of cartons. A 1.2 × 1.0 × 0.8 m carton is 0.96 CBM, so ten of them are 9.6 CBM. CBM is what LCL sea freight is priced on, and multiplying it by 167 gives the chargeable weight in kg for air freight.
What CBM stands for
CBM is short for cubic meter (also written m³ or CBM). In shipping it is the volume a shipment takes up — the amount of space it needs inside a container, truck or aircraft hold. Because freight is sold by the space it occupies as much as by its weight, CBM is the number every forwarder asks for first.
You will see it on quotes, packing lists and bills of lading. A shipment described as "9.6 CBM" occupies 9.6 cubic meters, regardless of how many individual cartons that is.
The CBM formula
CBM is just volume, so the formula is the volume of a box times how many boxes you have:
CBM = length (m) × width (m) × height (m) × quantity
Every dimension has to be in meters before you multiply. If you measured in centimeters, divide each side by 100 first — or multiply the three sides in centimeters and divide the result by 1,000,000 (because there are 1,000,000 cm³ in 1 m³).
Worked example
Say you have 10 cartons, each 120 × 100 × 80 cm:
| Step | Calculation | Result |
|---|---|---|
| Convert to meters | 120 cm → 1.2 m, 100 → 1.0, 80 → 0.8 | 1.2 × 1.0 × 0.8 m |
| Volume of one carton | 1.2 × 1.0 × 0.8 | 0.96 CBM |
| Multiply by quantity | 0.96 × 10 | 9.6 CBM |
So the shipment is 9.6 CBM. If the cartons were different sizes, you would work out each size separately and add the volumes together.
Why CBM matters for your freight cost
LCL sea freight is priced per revenue ton — whichever is greater, the weight in metric tons or the volume in CBM. For most manufactured goods the volume wins, so your CBM is what you actually pay for. One CBM of light cargo is billed as if it weighed 1,000 kg.
CBM also decides how much fits in a container. As a rule of thumb a 20ft holds about 33 usable CBM, a 40ft around 67, and a 40ft High Cube about 76. See our guide on how many CBM fit in a container for the full table.
CBM and chargeable weight
For air freight, CBM is converted into a billable weight. Multiply total CBM by 167 to get the volumetric weight in kilograms (that is the IATA 6000 divisor expressed per cubic meter). A 1.8 CBM shipment has a volumetric weight of about 300 kg, and you are billed on that or the actual weight, whichever is higher — see how to calculate chargeable weight.
Frequently asked questions
What does CBM mean in shipping?
CBM stands for cubic meter (m³) — the total volume your cargo occupies. It is the standard unit forwarders use to quote LCL (less-than-container-load) sea freight and to work out how much cargo fits in a container.
What is the CBM formula?
CBM = length × width × height, with every dimension in meters, multiplied by the number of cartons. A carton of 1.2 × 1.0 × 0.8 m is 0.96 CBM; ten of them is 9.6 CBM.
How do I calculate CBM from centimeters?
Multiply length × width × height in centimeters, then divide by 1,000,000 to convert cm³ to m³. For example 120 × 100 × 80 cm = 960,000 cm³ = 0.96 CBM.
How do I convert CBM to weight?
For air freight, multiply CBM by about 167 to get the volumetric (chargeable) weight in kg — that is the IATA 6000 divisor expressed per cubic meter. So 1.8 CBM ≈ 300 kg. For LCL sea freight, 1 CBM is charged as 1,000 kg (one revenue ton), whichever is greater.
Is CBM the same as volumetric weight?
No. CBM is pure volume in cubic meters. Volumetric (dimensional) weight converts that volume into a billable weight using a carrier divisor, so light but bulky cargo pays for the space it takes up.
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