Air cargo rates are based not only on actual weight but also on volumetric weight, which represents the space occupied by the shipment at a standard density. The formula is simple: length × width × height in centimetres, divided by 6000. The result is compared with the actual weight in kilograms, and the higher value is charged. The divisor 6000 is the IATA standard for air freight; road and courier services use other divisors, usually 4000–5000, so rates across transport modes cannot be compared directly.
This means that a light but bulky box, for example with clothing, toys or foam packaging, may cost more than a compact but heavy crate containing metal parts. Before dispatch, measure the external dimensions of the package, including the pallet and any protective crate, not only the goods inside.
Calculation example
A box measuring 60 × 50 × 40 cm has an actual weight of 12 kg. Its volumetric weight is (60 × 50 × 40) / 6000 = 20 kg. Since 20 is greater than 12, the shipment is charged at 20 kg. For several boxes, each piece is calculated separately and then added together. Do not round dimensions down, because they will be measured again at acceptance.
How to reduce volumetric weight
- Repack more tightly and remove unnecessary empty space;
- Use vacuum packaging for soft and textile goods;
- Use packaging that matches the actual product size instead of oversized multilayer boxes;
- For pallet shipments, avoid unnecessary height because the crate and pallet are also included in the dimensions.
If you are unsure of the final cost, send the manager the exact dimensions and weight of each piece. Calculating both values takes only a few minutes and makes it easier to decide whether repacking is worthwhile.