If you have ever been charged for more weight than your freight actually weighs, cubic weight is the reason. Almost every freight carrier in Australia uses it. This guide explains what it is, how to calculate it, and how to keep your freight costs down.
Why carriers use cubic weight
A truck fills up by space as well as by weight. A carton of pillows takes up the same room as a carton of tiles but weighs a fraction as much. If freight were charged on weight alone, light, bulky items would travel almost free while using the space that heavy freight needs. Cubic weight converts the space your freight takes up into a weight, so both are charged fairly.
How to calculate cubic weight
- Measure the length, width and height of each item in metres.
- Multiply them together to get the volume in cubic metres (m³).
- Multiply the cubic metres by the conversion factor. For road freight this is commonly 250 kg per cubic metre.
The result is the cubic weight. You are charged on whichever is greater: the actual (dead) weight or the cubic weight. That figure is called the chargeable weight.
Worked examples
| Item | Dimensions | Cubic m³ | Cubic weight | Actual weight | Charged on |
|---|---|---|---|---|---|
| Carton of cushions | 60 × 40 × 40 cm | 0.096 | 24 kg | 6 kg | 24 kg (cubic) |
| Carton of tiles | 40 × 30 × 20 cm | 0.024 | 6 kg | 22 kg | 22 kg (actual) |
| Standard pallet | 120 × 120 × 140 cm | 2.016 | 504 kg | 450 kg | 504 kg (cubic) |
Use our free cubic weight calculator to work out your own freight.
Road, air and other conversion factors
Conversion factors vary by carrier and transport mode. Many Australian road carriers use 250 kg per cubic metre, some use 333, and air freight is commonly calculated at about 167 kg per cubic metre (a 1:6000 divisor). Always check which factor your carrier uses. We use 250 kg per cubic metre for road freight.
Six ways to reduce your freight costs
- Right-size your cartons. Empty space inside a box is still charged.
- Combine items into fewer, well-packed cartons or onto one pallet.
- Measure accurately. Under-declared freight is re-measured and re-charged, often with an admin fee.
- Avoid overhang on pallets. It adds to the measured size and risks damage.
- Send regularly with one carrier. Regular senders qualify for account pricing.
- Book ahead. Planned pickups cost less than urgent ones.
Published by All Freight Carrying, Yandina, Sunshine Coast · 20 October 2026 · Last updated 25 October 2026
