Add your carton dimensions once and see the chargeable weight for every channel side by side — express at 5000, air and postal at 6000, LCL on W/M. Then look at the density figure to see which channel your product actually belongs in.
| Channel | Divisor | Vol. kg | Chargeable | Billed on |
|---|
Carriers bill the greater of actual weight and volumetric weight, where volumetric weight is the parcel's volume in cm³ divided by a divisor. The divisor is the only thing that changes between channels — and it changes the answer a lot.
volumetric weight (kg) = L × W × H (cm) ÷ divisor
| Channel | Divisor | Equivalent | Where it is used |
|---|---|---|---|
| DHL Express, FedEx, UPS, TNT | 5000 | 1 cbm = 200 kg | International express parcels |
| SF Express, EMS, postal | 6000 | 1 cbm = 167 kg | China-origin express and ePacket |
| Air freight (IATA) | 6000 | 1 cbm = 166.67 kg | Air cargo, chargeable weight per AWB |
| Sea LCL | 1000 | 1 cbm = 1,000 kg | W/M — revenue ton is the greater of cbm and metric ton |
| Road LTL | 3000 | 1 cbm = 333 kg | Groupage, varies by carrier |
Some negotiated contracts still use 6000 for UPS or FedEx. If your rate card says 6000, override the divisor field — the calculator will use yours instead of the default.
Density, not weight, tells you which channel is rational. Each divisor implies a break-even density where actual weight equals volumetric weight: 1,000,000 ÷ divisor.
A carton of cosmetics sits around 150–250 kg per cbm. A carton of plush toys sits near 60. The cosmetics shipment is roughly at its express break-even; the toys are paying for 2.5× their real weight, and sea freight becomes correct long before the volume gets large.
Measuring the product, not the carton. Every dimension that matters is the outside of the shipper, after packing. A 40 cm product in a 44 cm carton is 10% more volume before you consider the master carton.
Ignoring the master carton. Express is priced per parcel. If six inner boxes ship as one master carton, the volumetric weight is computed on the master — usually a 5–15% saving against six separate parcels, because packing efficiency beats shipping air between boxes.
Assuming LCL is cheap because the rate is small. LCL is billed on W/M plus a stack of fixed per-shipment charges — documentation, THC, CFS handling, destination fees. Below about 3–5 cbm those fixed charges dominate the freight rate, and it is worth comparing against air.
Once you know the chargeable weight, the rate is a single multiplication. Put the resulting freight into the landed cost calculator to see what it does to your cost per unit — air freight on a light product often adds more per unit than the duty does.
The calculator gives you the answer. These guides give you the reasoning, so you can tell when the answer is wrong.
The volumetric weight formula, which divisor applies to air, express and LCL, and how carton density tells you whether you pay for space or weight.
Read the guide → Freight · 7 minWhy the nominal cbm on a container spec is not the capacity you get, how packing and the weight ceiling decide the real count, and what pallets cost.
Read the guide →