If you import or export goods, CBM is one of the first numbers your freight forwarder will ask for. It decides how much space your cargo takes in a container, and for sea freight it is usually the basis of the price you pay.
What does CBM mean?
CBM stands for cubic metre (m³). One CBM is the volume of a box measuring 1 metre long, 1 metre wide and 1 metre high. In shipping, CBM measures how much space a carton, a pallet or a whole shipment occupies.
The CBM formula
For a single carton measured in centimetres:
We divide by 1,000,000 because one cubic metre contains 100 × 100 × 100 = 1,000,000 cubic centimetres.
For a shipment with many identical cartons:
Worked example
You are shipping 120 cartons, each measuring 60 × 40 × 50 cm.
- One carton: 60 × 40 × 50 = 120,000 cm³
- 120,000 ÷ 1,000,000 = 0.12 CBM per carton
- 0.12 × 120 cartons = 14.4 CBM in total
At a sea freight rate of $85 per CBM, the basic freight would be 14.4 × 85 = $1,224.
CBM from inches or metres
- Metres: multiply length × width × height directly. A 0.6 × 0.4 × 0.5 m carton is 0.12 CBM.
- Inches: multiply the three dimensions and divide by 61,024. A 24 × 16 × 20 in carton is 7,680 ÷ 61,024 ≈ 0.126 CBM.
Why CBM matters
- Sea freight price. LCL (less than container load) shipments are normally charged per CBM, often with a minimum of 1 CBM.
- Weight or measure. Many carriers charge on "W/M": 1 CBM is compared with 1,000 kg, and you pay on whichever is greater. Light, bulky goods are charged by volume; dense goods by weight.
- Container choice. Total CBM tells you whether a 20FT or 40FT container makes more sense than shipping LCL.
- Warehouse space. Storage and handling fees are often based on volume too.
Common CBM mistakes
- Measuring the product instead of the outer carton.
- Forgetting packaging that sticks out, such as handles or pallet overhang.
- Mixing units (centimetres for one carton, inches for another).
- Rounding each carton too early. Calculate with full precision and round the total.
Calculate CBM faster
Doing this by hand for every product is slow and error-prone. In MYCBM's Sea Freight Calculator you enter the carton dimensions, the number of cartons and your rate per CBM, and the total CBM, shipping cost and container fill estimate update as you type — in Arabic, English or French.
Related reading: How to calculate sea freight cost using CBM and How many CBM fit in a shipping container?
Try the calculator from this guide
Calculate CBM, freight costs and container fill in seconds with MYCBM.
