CBM and Chargeable Weight for PNG Shipments: How Freight Is Measured and Charged
Freight is rarely charged on weight alone. Here’s how to calculate cubic metres and chargeable weight for sea and air freight to PNG, with worked examples and practical ways to reduce what you pay.
In this guide
- CBM is length × width × height in metres.
- LCL sea freight is charged per revenue tonne: the greater of weight in tonnes or volume in cubic metres.
- Air freight usually uses a volumetric factor of 6,000, so one cubic metre counts as about 167 kilograms.
- Measuring accurately and packing tightly directly reduces freight costs.
Calculating cubic metres (CBM)
To find the volume of a package in cubic metres, multiply its length, width and height in metres. For a whole consignment, add up the volume of every package.
Measure the outermost points of each package, including pallet overhang, handles and protrusions. Freight is charged on the space your cargo takes up, not the size of the product inside it.
Sea freight: revenue tonnes
LCL sea freight is charged per revenue tonne, sometimes written as W/M, meaning weight or measure. Each cubic metre is compared with each tonne, and whichever is greater is used, usually with a minimum of one revenue tonne.
| Shipment | Volume | Weight | Revenue tonnes charged |
|---|---|---|---|
| Furniture | 6 CBM | 1.2 tonnes | 6 (volume is greater) |
| Steel parts | 2 CBM | 4.5 tonnes | 4.5 (weight is greater) |
| Small carton lot | 0.4 CBM | 0.1 tonnes | 1 (minimum charge) |
FCL is charged per container, so CBM matters mainly for working out how many containers you need and whether the cargo fits.
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Air freight: chargeable weight
Air freight is charged on chargeable weight: the greater of the actual gross weight and the volumetric weight. Airlines commonly calculate volumetric weight by multiplying length × width × height in centimetres and dividing by 6,000. That means one cubic metre counts as about 167 kilograms. Courier and express services often use a divisor of 5,000, which makes light, bulky parcels even more expensive.
Air rates are also commonly tiered by weight breaks, so the rate per kilogram drops as the chargeable weight passes certain thresholds.
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Pallets and container loading
Pallet size has a big effect on how efficiently a container is used. Pallets measuring 1,200 by 1,000 millimetres fit ISO containers well, while Australian standard pallets, which are 1,165 millimetres square, leave more wasted space. If you’re loading a full container, ask your forwarder or supplier for a load plan showing how many pallets will fit and how they’ll be stacked.
For LCL, every pallet is charged on its full footprint and height, so a half-empty pallet costs as much as a full one of the same dimensions.
Domestic legs in PNG
The same principles apply to many domestic movements. Domestic air freight in PNG is charged on chargeable weight, and coastal shipping for general cargo is often charged per revenue tonne. On small aircraft, dimensions can also be a hard limit, regardless of what you’re prepared to pay.
Reducing what you pay
- Measure and weigh accurately before booking, so you aren’t re-charged at the terminal.
- Remove unnecessary outer packaging and empty space in cartons.
- Flat-pack or disassemble bulky items where practical.
- Use pallet sizes that make the most of container dimensions.
- Stack cargo where its strength allows, and mark non-stackable pieces clearly.
- Consolidate light, bulky items with heavier cargo in the same container.
Frequently asked questions
How do I calculate CBM?
Multiply length × width × height in metres for each package, then add up all the packages.
What is a revenue tonne?
The greater of the weight in tonnes or the volume in cubic metres, used to charge LCL sea freight.
How is air freight chargeable weight calculated?
It’s the greater of actual weight and volumetric weight. Volumetric weight is commonly length × width × height in centimetres divided by 6,000.
Why was I charged more than the weight of my cargo?
Because the cargo’s volume produced a higher volumetric or revenue tonne figure than its actual weight.
More on shipping modes, transit times and costs
Philip Thomas
Philip is the lead author and editor at Phantom8. He writes practical guides to shipping freight into Papua New Guinea, with a focus on choosing the right port, clearing customs and planning the inland leg.
General information only. This guide is general in nature and isn’t legal, customs or logistics advice for your specific shipment. Port operations, road conditions, schedules and charges change, so confirm the details with your freight forwarder, transport operator or the relevant authority before you ship.