Chargeable weight calculator for air freight (volumetric weight)
Air freight is charged on the higher of the gross weight and the volume weight: length × width × height in cm ÷ 6,000, under the IATA rules airlines rate cargo by. Two cartons of 40 × 50 × 50 cm weighing 25.0 kg together have a volume weight of 33.333 kg, so the chargeable weight is 33.5 kg.
Worked example
Two cartons of 40 × 50 × 50 cm, 25.0 kg gross in total.
- Volume: 40 × 50 × 50 × 2 = 200,000 cm³ (0.2 m³).
- Volume weight: 200,000 ÷ 6,000 = 33.333 kg, worked to three decimal places.
- The volume weight is higher than the 25.0 kg gross weight, so the consignment is charged on volume.
- Rounded up to the next half kilogram: 33.5 kg chargeable.
How is chargeable weight calculated for air freight?
- Measure each package at its greatest length, width and height. Round each dimension to the nearest whole centimetre: half a centimetre or more goes up, less goes down.
- Multiply the three and the number of packages, and add the packages together for the volume in cm³.
- Divide by 6,000 for the volume weight in kg, worked to three decimal places.
- Compare it with the gross weight. The higher of the two is the chargeable weight.
- Round up to the next half kilogram: 0.1 to 0.4 becomes .5, above .5 becomes the next whole kilogram, exactly .5 stays.
Why divide by 6,000?
The IATA rules treat 6,000 cm³ as weighing at least 1 kg, a density of about 166.67 kg per cubic metre. Cargo lighter than that pays for the space it takes rather than its weight. The rules list a few exceptions, such as 7,000 cm³ per kg for cut flowers and live plants from India. Express courier services are priced on their own terms and may use a different divisor; a smaller divisor makes the same carton heavier on the invoice.
How many kg is 1 CBM in air freight?
At the 6,000 divisor, 1 CBM is charged as at least 166.67 kg (1,000,000 ÷ 6,000). A shipment of 1 CBM that weighs 100 kg is charged on 167 kg; one that weighs 250 kg is charged on 250 kg.
Related tools and guides
Sources
Rules checked on 23 October 2026
IATA states the general rule: the volume in cm³ divided by 6,000, charged on whichever is higher of the volumetric and actual weight. The rounding rules and TACT Rules 3.9.4 are as reproduced in the ASEAN common logistics curriculum, Chapter 5: Calculation of Air Freight, which also supplies the worked example. The TACT rules manual itself is sold by IATA.
- IATA Knowledge Hub: Air cargo tariffs and rules, what you need to know (volume ÷ 6,000; higher of volumetric and actual weight)
- ASEAN common logistics curriculum, Chapter 5: Calculation of Air Freight (IATA TACT Rules 3.9.4, dimension and weight rounding)
- IATA: The Air Cargo Tariff and Rules (TACT)
Cite this tool:Cambridge China Bridge, Chargeable weight calculator for air freight, https://camchinabridge.co.uk/tools/chargeable-weight-calculator/ (rules checked 23 October 2026).
Air cargo rule as IATA publishes it. A carrier or forwarder may set a different divisor, minimum charge or rounding in its own terms, and the quote you accept governs what you pay.
Questions about this tool
What is the formula for volumetric weight in air freight?
Length × width × height in centimetres ÷ 6,000 gives the volume weight in kilograms. The chargeable weight is the higher of that and the gross weight, rounded up to the next half kilogram.
What is the chargeable weight of two 40 × 50 × 50 cm cartons weighing 25.0 kg?
The volume is 200,000 cm³, so the volume weight is 33.333 kg. That beats the 25.0 kg gross weight, and rounded up to the next half kilogram the chargeable weight is 33.5 kg.
Is volumetric weight calculated per carton or for the whole shipment?
Under the IATA rules the volume of a consignment is the total of its packages, and the volume weight and chargeable weight are worked out once for the whole consignment, with the rounding at the end.
Do couriers use 6,000 or 5,000?
6,000 is the IATA figure for air cargo. Express courier services publish their own divisor in their terms, and it may differ; a smaller divisor makes the same carton weigh more on the invoice. Use the divisor on your quote.
How do I lower my chargeable weight?
Cut the empty space: ask the factory for a smaller carton or fewer, fuller cartons, and avoid oversized outer packaging. Below about 167 kg per cubic metre you pay for space, so a smaller box saves more than a lighter one.