Air freight is commonly rated on chargeable weight, which means the shipment is not priced only by what it weighs on a scale. Carriers and forwarders compare actual gross weight with a volumetric weight derived from shipment dimensions and use the higher applicable figure for rating.
This matters most for lightweight, bulky cargo. A shipment of foam products may weigh far less than dense machinery, but it consumes aircraft space that cannot be sold to another shipper.
Actual weight vs volumetric weight
| Measure | What it represents |
|---|---|
| Actual/gross weight | Physical shipment weight on the scale |
| Volumetric weight | Space-equivalent weight calculated from dimensions |
| Chargeable weight | The higher applicable rating weight |
Maersk’s air-cargo guidance describes chargeable weight as the higher of gross and volumetric weight. The exact dimensional factor can vary by carrier, route and agreement, so the quote or tariff always controls.
Common planning formula
A widely used metric planning convention is:
Volumetric weight (kg) = length × width × height in cm ÷ 6,000
This is a useful planning assumption, not a universal rule. Some services or forwarders can use a different factor.
Worked example
Suppose four cartons each measure 60 × 50 × 40 cm and weigh 12 kg.
- Total actual weight = 48 kg.
- Volume per carton = 120,000 cm³.
- Planning volumetric weight per carton at 6,000 = 20 kg.
- Total volumetric weight = 80 kg.
In that scenario, 80 kg is the planning chargeable weight because it exceeds 48 kg actual weight.
If the carton can safely be reduced to 50 × 45 × 35 cm, the planning volumetric weight falls to about 13.1 kg per carton. Across four cartons, that is about 52.5 kg—much closer to actual weight.
Why packaging engineering matters
Reducing air in the box can directly reduce chargeable weight until actual weight becomes the controlling figure. Test package options with the Volumetric Weight Calculator and compare actual versus dimensional results with the Billable Weight Calculator.
Do not confuse air and parcel DIM factors
Parcel carriers in the United States often publish formulas using a 139 cubic-inch divisor for certain services, while air-cargo quotes may use metric volume factors such as 6,000 cm³/kg. Applying a parcel formula to an air-freight quote can produce the wrong estimate.
How to audit an air quote
- Confirm the number of pieces.
- Check the packed dimensions of every piece.
- Verify the dimensional factor used by the forwarder.
- Calculate actual and volumetric totals.
- Confirm how fractions and minimum weights are rounded.
- Separate transportation from screening, handling, pickup and destination charges.
For modal comparison, see Air Freight vs Ocean Freight.
Frequently asked questions
Is 6,000 always the air-freight divisor?
No. It is a common planning convention, but the carrier, forwarder, route and contract can use another factor.
Can chargeable weight be lower than actual weight?
Not under the normal higher-of-actual-or-volumetric logic. Actual weight provides the floor.
Does pallet size count?
Yes. If cargo is tendered on a pallet, the rated dimensions can reflect the full shipping unit. Confirm the forwarder’s measurement method.
Sources
PackToolbox guides are built around stated formulas, practical examples and source checks for changeable carrier, freight and logistics rules. Calculators are planning aids; final requirements should be verified with the relevant carrier or service provider.