Mr Kcal insight
How to Calculate CBM for China Shipping
CBM is one of the first numbers buyers need before comparing sea freight, air freight, or container loading assumptions.
CBM formula
For carton dimensions in centimeters, multiply length by width by height and divide by 1,000,000. Then multiply by the number of cartons. For meters, multiply length by width by height directly.
Why suppliers must provide carton data
A product unit size is not enough for freight quotes. Ask for export carton length, width, height, gross weight, net weight, carton quantity, and packing method.
CBM versus volumetric weight
CBM measures volume. Volumetric weight converts volume into a billable weight using a divisor such as 5000 or 6000 for air and express estimates.
Checklist
Confirm carton dimensions, carton count, gross weight, whether pallets are used, and whether the cartons are final production cartons before requesting freight quotes.
Related tools and guides
Disclaimer
This guide is for general planning only. Confirm commercial, customs, tax, legal, and logistics decisions with qualified professionals or the relevant service provider.
CBM guide
Calculate carton volume before discussing freight.
CBM means cubic meters. For carton dimensions in centimeters, multiply length by width by height, then divide by 1,000,000. CBM is a volume measure, while volumetric weight is a chargeable-weight estimate used by many carriers.
Formula
CBM per carton = length cm x width cm x height cm / 1,000,000. Total CBM = CBM per carton x carton quantity.
Supplier data
Ask for packed carton dimensions, carton quantity, gross weight, net weight, and whether cartons are palletized.
Quote preparation
Share CBM, weight, pickup city, destination, Incoterms, and ready date when asking a forwarder for a quote.
Before you use the result
- Do not use product size when the packed carton size is different.
- Do not confuse CBM with air express volumetric weight.
- Confirm final carton data after production packing is complete.
Build a carton table that survives the freight quote.
CBM is simple arithmetic, but quote errors usually come from unfinished packaging, mixed units, missing carton types, or a supplier total that cannot be traced back to packing data.
Use the formula that matches the recorded unit
- Centimeters: L x W x H x quantity / 1,000,000.
- Meters: L x W x H x quantity.
- Inches: cubic inches / 61,023.744.
- Calculate mixed cartons as separate rows and add the CBM totals.
Ask the supplier for final packing data
- Outer carton dimensions and units.
- Units per carton and carton count by SKU.
- Net and gross weight per carton.
- Pallet or wooden-case dimensions when used.
- Packing-list revision date and shipment readiness date.
Send volume with the facts that price freight
- Total CBM and total gross weight.
- Commodity and packaging state.
- Factory pickup city and destination.
- Incoterm and named place.
- Expected cargo-ready date and any special handling.
Three carton types should never be averaged into one row
If 40 cartons are 50 x 40 x 30 cm, 20 cartons are 60 x 45 x 35 cm, and 5 wooden cases are 1.2 x 0.8 x 0.9 m, calculate 2.4 m3, 1.89 m3, and 4.32 m3 separately. The total is 8.61 m3 before any additional pallet or loading allowance.