Chargeable weight is the weight an airline actually bills, and it is the greater of a shipment’s actual gross weight and its volumetric weight. Volumetric weight is calculated by multiplying length, width and height in centimetres and dividing by 6000, the divisor IATA sets as the air freight standard.
The rule exists because aircraft run out of space before they run out of payload. A consignment of pillows and a consignment of machine parts can weigh the same on a scale while occupying completely different amounts of a freighter. Chargeable weight is how the airline is paid for the space a shipment takes up rather than only for its mass.
It appears as a field on the air waybill, and it is the figure every air freight rate is multiplied by.
How Is Chargeable Weight Calculated?
Chargeable weight is calculated in three steps.
- Weigh the shipment to get the actual gross weight in kilograms
- Calculate the volumetric weight by multiplying length, width and height in centimetres and dividing by 6000
- Compare the two figures and take the higher one
The formula for the second step is:
Volumetric weight in kg = (length cm × width cm × height cm) ÷ 6000
Nothing else changes the outcome. Whichever figure is larger becomes the chargeable weight, and that is the number the rate per kilogram is applied to.
Worked Examples
The table below shows how the same calculation produces different outcomes depending on the density of the cargo.
| Shipment | Dimensions in cm | Volume in cm³ | Volumetric weight | Actual weight | Chargeable weight |
|---|---|---|---|---|---|
| Machine parts | 100 × 80 × 60 | 480,000 | 80 kg | 100 kg | 100 kg, actual weight wins |
| Packaged textiles | 120 × 100 × 80 | 960,000 | 160 kg | 50 kg | 160 kg, volumetric wins |
| Electronics carton | 60 × 50 × 40 | 120,000 | 20 kg | 15 kg | 20 kg, volumetric wins |
| Mixed consignment | 90 × 50 × 80 | 360,000 | 60 kg | 25 kg | 60 kg, volumetric wins |
In the second example, the shipper pays for 160 kg while the scale reads 50 kg. At a rate of USD 5.00 per kilogram, that is USD 800 rather than USD 250. The gap is the cost of low-density cargo, and it is why packaging decisions change freight bills.
What Is the Density Point Where Volumetric Takes Over?
A shipment lighter than roughly 167 kilograms per cubic metre is charged on volumetric weight, and anything denser is charged on actual weight. That single figure replaces the whole calculation as a quick test.
The arithmetic is straightforward. A cubic metre contains 1,000,000 cubic centimetres. Divided by the 6000 divisor, that gives 166.7 kilograms. So the divisor is really a density rule expressed as a formula.
In practice this means:
- Dense cargo such as machinery, metals, liquids and printed matter is almost always billed on actual weight
- Low-density cargo such as textiles, packaging, furniture, empty containers and most consumer goods in retail packaging is almost always billed on volumetric weight
- Anything close to the line is worth measuring carefully, because small packaging changes can flip which figure applies
Why Is the Divisor 6000?
The 6000 divisor reflects the usable density of an aircraft hold, and it converts volume into a weight equivalent so that a single rate per kilogram can price both dense and bulky cargo.
It is not a universal number. Different services use different divisors, and the divisor is one of the things a rate card actually specifies.
| Service | Divisor | Equivalent density |
|---|---|---|
| Standard air freight, the IATA benchmark | 6000 | Roughly 167 kg per m³ |
| Express and courier services | 5000 | 200 kg per m³ |
| Imperial calculation, inches and pounds | Approximately 166 | Same ratio expressed in imperial units |
A 5000 divisor produces around 20 percent more volumetric weight than 6000 on identical cargo, which is why an express quote and an air freight quote on the same cartons can differ far more than the headline rate suggests.
Always check the divisor on the quote. If the rate card does not state one, ask before comparing prices.
Is Chargeable Weight Calculated Per Package or Per Shipment?
Volumetric weight is normally calculated per package and then totalled, rather than by measuring the whole consignment as one block. The comparison against actual weight is then made at consignment level.
This distinction matters and it is where disputes start.
- Calculating per package captures the space each carton genuinely occupies, including irregular shapes
- Measuring a consolidated consignment as a single cube can understate or overstate the volume, depending on how the pieces stack
- Rounding, where applied per package, compounds across a large shipment
For a palletised consignment, the built unit is usually measured as presented, including the pallet base and any overhang. This is one of the reasons how a shipment is built changes what it costs, and it connects directly to ULD and air cargo container selection on shipper-built units.
How Does Rounding Affect the Final Figure?
Carriers round chargeable weight up, usually to the next half kilogram or the next full kilogram, and the rounding is applied before the rate is multiplied.
Rounding practice varies by carrier and by contract, which means two forwarders quoting the same rate on the same cargo can produce different invoices. On a single small carton the difference is trivial. Across hundreds of pieces it is not.
Three things to check on any quote.
- Whether rounding is to the next 0.5 kg or the next 1 kg
- Whether rounding is applied per package or once at consignment level
- Whether a minimum charge applies, since very small shipments are often billed at a floor rather than at chargeable weight
How Can a Shipper Reduce Chargeable Weight?
Chargeable weight falls when density rises, so the practical lever is packaging rather than negotiation.
- Remove void space inside cartons, since air inside a box is billed at the volumetric rate
- Right-size the carton to the goods rather than using a standard box for everything
- Where goods allow, compress or nest items to cut total volume
- Avoid overhang on built units, since the measured footprint usually includes it
- Review whether the consignment is close to the 167 kg per m³ line, because small changes flip the calculation entirely
None of this applies to genuinely dense cargo. If the shipment is already charged on actual weight, reducing volume changes nothing.
Questions About Chargeable Weight
What is chargeable weight in air freight?
Chargeable weight is the weight an airline bills on, and it is the greater of the shipment’s actual gross weight and its volumetric weight. It appears as a field on the air waybill and it is the figure the rate per kilogram is applied to.
What is the formula for volumetric weight in air freight?
Volumetric weight in kilograms equals length in centimetres multiplied by width in centimetres multiplied by height in centimetres, divided by 6000. The 6000 divisor is the IATA air freight standard.
What is the difference between actual weight and chargeable weight?
Actual weight is what the shipment reads on a scale. Chargeable weight is the greater of that figure and the volumetric weight calculated from the dimensions. For dense cargo the two are the same, and for bulky cargo the chargeable weight is higher.
Why is the air freight divisor 6000 and not 5000?
6000 is the IATA standard for air freight, and it corresponds to a density of roughly 167 kilograms per cubic metre. Express and courier services generally use 5000, which corresponds to 200 kilograms per cubic metre and produces around 20 percent more volumetric weight on the same cargo.
Do all airlines use the same divisor?
Most use 6000 for standard air freight, but the divisor is set by the carrier or the contract, so it should be confirmed on the rate card. A quote that does not state the divisor cannot be compared reliably with one that does.
Is chargeable weight the same as dimensional weight?
No. Dimensional weight, also called volumetric weight, is the figure calculated from the dimensions. Chargeable weight is whichever is higher, the dimensional weight or the actual weight.
Does the pallet count towards chargeable weight?
On a built unit the measurement is normally taken as presented, which includes the pallet base and any overhang beyond it. Overhang in particular adds volume without adding useful capacity, so it is worth avoiding.
