Six thousand or five: the air freight divisor

In air freight you do not pay for what the shipment weighs, but for how much space it takes up — if it takes up more space than it weighs. The calculation is simple: the volume of the shipment in cubic centimetres is divided by the divisor, and the result is the volumetric weight in kilograms. The higher of the two figures is charged — the actual or the volumetric weight.

The standard air freight divisor is 6000. That means 167 kilograms per cubic metre. In international courier shipments the usual divisor is 5000, which is 200 kilograms per cubic metre.

The difference between them is twenty per cent of the volumetric weight. And because air shipments are usually voluminous rather than heavy, that means twenty per cent of the entire freight charge.

Where it breaks

The divisor is a contractual matter. It is written into the quotation or the rate agreement. The problem is that it is usually not written on the invoice — only the result is, the chargeable weight in kilograms.

That means the invoice cannot be checked without the dimensions. You see “Chargeable weight 312 kg” and have nothing from which to establish whether that is 6000, or 5000, or something in between.

In practice there are three cases. First: 6000 was agreed, 5000 was applied, because that is how the default is set in the operator’s system. Second: the courier divisor of 5000 was applied to general air freight, because the shipment was handed over to the courier division. Third, and the most common: nobody even knows which divisor applies, because the contract does not state one, and then there is no ground for a dispute.

The last case is the most important one, because it can be settled with a single sentence in the contract. If the contract has no divisor, add it at the next renewal. This is one of the few places in logistics contracts where one number in one place closes an entire category of errors.

How to check it yourself

You need three things from the same shipment: the dimensions per package, the gross weight and the chargeable weight stated on the invoice.

Work out the volume — length × width × height in centimetres for each package, multiplied by the number of packages, all added together. Divide by 6000. Compare with the gross weight, take the higher figure, round up to 0.5 kg.

If your figure is lower than the one on the invoice, there are three possible reasons: a different divisor was applied, each package was rounded separately, or the dimensions were rounded up. All three are cleared up with one email, if you know what to ask.

Why this is not a small matter

Chargeable weight is not one line on the invoice. It is the basis on which the freight charge, the fuel surcharge, the security surcharge and often the screening fee are calculated. An error in the weight is not an error in one line — it is in four.

So a twenty per cent error in the divisor is not twenty per cent of the freight line. It is twenty per cent of almost the whole invoice.