Calculate each packed carton type, then add the rows
CBM means cubic meters: a measure of volume. Start with final outer-carton dimensions and the number of cartons of each size. A freight forwarder will also need packed gross weight, commodity, route and packing state.
The formula depends on the dimension unit
- Centimeters: length × width × height × cartons ÷ 1,000,000.
- Meters: length × width × height × cartons.
- Inches: length × width × height × cartons × 0.000016387064.
Worked example with two carton sizes
| Carton type | Outer size | Cartons | CBM each | Total CBM |
|---|---|---|---|---|
| A | 50 × 40 × 30 cm | 10 | 0.060 | 0.600 |
| B | 60 × 40 × 35 cm | 5 | 0.084 | 0.420 |
| Total | Two separate packing configurations | 15 | — | 1.020 |
Do not average the two sets of dimensions before calculating. Keep each row so a supplier or forwarder can check it.
What to ask the supplier
Request the final outer dimensions, carton count, units per carton and net/gross weight by packing type. Ask whether pallets, crates, corner protection or other packing will be added. If the cargo is palletized, confirm the final pallet footprint and height rather than adding an arbitrary allowance.
CBM does not determine the freight bill alone
Air and courier services can convert volume to dimensional weight. Sea freight can involve weight/measurement rules, minimums and destination charges. Obtain a current quote with the route, service and packing details; do not turn a volume result into a promised shipping price.
Calculate mixed-carton CBM and download the breakdown · Compare actual and volumetric weight
For the complete data handoff, use the freight-ready carton data checklist. This guide explains the arithmetic; the checklist explains the information to send.