Air freight chargeable weight (CW) calculator

What is chargeable weight (CW)

On an aircraft the limit is not weight alone; the volume of the cargo hold is limited too. A light but bulky shipment can take up a large part of the hold while staying far below the kilograms the aircraft could carry. If the carrier charged by the kilogram alone in that case, it would lose money.

The solution is to convert the space occupied into a weight equivalent. This value is called the volumetric weight. The invoice is issued on whichever is greater: the gross weight (GW) or the volumetric weight; this is called the chargeable weight (CW).

Why a divisor of 6000

The common divisor in air cargo is 6000. When you divide a carton’s length × width × height in centimetres by 6000, you get its volumetric weight in kilograms. This prices one cubic metre at roughly 167 kg.

Express carriers mostly apply 5000 — the same volume counts as heavier, which means it costs more. These values are established in the industry but may vary by carrier; which divisor is applied should be confirmed in writing in the quotation.

Calculation for multi-line shipments

A shipment may contain carton groups of different sizes. The correct method is to calculate each group separately and add them up:

• Volumetric weight per box for each group = length × width × height ÷ divisor
• Group VW = volumetric weight per box × number of boxes in the group
• Group GW = gross weight per box × number of boxes
• Total VW and total GW are the sums across all groups; chargeable weight (CW) = max(total GW, total VW), rounded up to the next 0.5 kg (IATA). Dimensions are rounded to the nearest centimetre.

Example

10 boxes, box size 70×50×50 cm, gross weight per box 10 kg:

• VW per box = 70 × 50 × 50 ÷ 6000 = 29.167 kg
• Total VW = 10 × 29.167 = 291.67 kg
• Total GW = 10 × 10 = 100 kg
• The total VW (291.67) is greater than the total GW (100); rounded up to the next 0.5 kg, the chargeable weight (CW) is 292 kg and the invoice is issued on this value.

The most effective way to cut cost

If volumetric weight is what determines the invoice, trying to reduce the actual weight is pointless. What works is reducing the box size and eliminating empty space. Determining the correct packaging size per product is a one-off task; the saving repeats on every shipment.