Reviewed November 2026. Formulas are shown above the guide. Report an error or request a calculator.
Actual weight versus volumetric weight
Air carriers charge for whichever is larger: what a shipment weighs or how much space it takes. The space is converted into a "volumetric" weight by dividing the volume by a fixed divisor. Airlines use the IATA divisor of 6,000 cm³ per kg (166 in³ per lb). Express couriers such as DHL, FedEx and UPS usually use 5,000 (139 in³ per lb), which makes the same box heavier on paper.
Worked example
Four cartons of 60 × 50 × 45 cm, each weighing 12 kg:
| Item | Airline (6000) | Courier (5000) |
|---|---|---|
| Actual weight | 48 kg | 48 kg |
| Volumetric weight | 90 kg | 108 kg |
| Chargeable weight | 90 kg | 108 kg |
The cartons are billed at almost twice their real weight. Repacking into smaller cartons with less void fill would cut the bill directly.
Ways to lower chargeable weight
- Right-size cartons and remove empty space; each centimetre counts in all three dimensions.
- Combine small parcels into one consolidated shipment so the airline divisor applies instead of the courier divisor.
- For heavy but compact goods, volumetric weight rarely matters; focus on the actual weight instead.
Frequently asked questions
How do I calculate volumetric weight?
Multiply length × width × height in centimetres and divide by 6,000 for airlines or 5,000 for express couriers. In inches, divide by 166 or 139 to get pounds.
What is chargeable weight?
The greater of the actual gross weight and the volumetric weight, usually rounded up to the next half kilogram.
Why do couriers use 5000 instead of 6000?
A smaller divisor gives a higher volumetric weight, reflecting the higher handling cost of small parcels in express networks.
Is chargeable weight calculated per piece or per shipment?
Airlines usually calculate it on the whole shipment. Couriers may calculate per package, so check your contract.