Can I reduce chargeable weight by repackaging a shipment?

Sometimes, yes — reducing dead space in oversized packaging (right-sizing cartons, avoiding unnecessary void fill) can lower volumetric weight without changing actual weight, which can meaningfully reduce chargeable weight on light, bulky cargo. It's worth checking before booking a shipment you suspect is over-boxed.

Does chargeable weight affect the CBSA duty and tax calculation?

No — duty and GST are calculated on the customs value for duty, not on chargeable weight. Chargeable weight only determines the freight cost itself, a separate calculation from the customs value that duty and GST apply to.

Is chargeable weight rounded?

Most carriers round chargeable weight up to the nearest 0.5kg — confirm this with your specific carrier since it's a standard but not universal practice.

Air Freight Fundamentals

Chargeable Weight & Dimensional Weight, Explained

Air freight is priced on whichever is greater — actual weight or volumetric (dimensional) weight — not simply on what the scale reads.

Get a Rate

6000

IATA standard volumetric divisor (cm³ per kg)

366

Equivalent divisor in inches³ per lb

Greater of two

Chargeable weight rule

Per piece or per shipment

Calculation basis, carrier-dependent

Why volume can cost more than weight

Aircraft cargo holds run out of space before they run out of weight capacity on most low-density freight. To price that fairly, IATA's standard formula converts a shipment's volume into an equivalent 'volumetric weight': length × width × height (in cm) divided by 6000 gives the volumetric weight in kilograms. The chargeable weight used to calculate freight cost is whichever is greater — actual gross weight or volumetric weight.

The 6000 divisor is the IATA/TACT industry standard for air freight; some couriers and some domestic services use different divisors (5000 is common for certain express networks), which is why a rate quoted by a courier can differ from an air freight forwarder's quote on an identical box. Confirm which divisor your specific carrier uses rather than assuming 6000 applies universally.

For consolidated shipments with multiple pieces of different densities, the chargeable weight calculation is typically done per piece then summed, though some carriers calculate on total shipment volume and total shipment weight instead — the two methods can produce slightly different results on a mixed-density shipment.

Calculating chargeable weight

Four steps to determine what you'll actually be charged for.

Measure each piece

Length, width, and height in centimetres, for every piece in the shipment — not just the largest one.

Calculate volumetric weight

L × W × H (cm) ÷ 6000 = volumetric weight in kg, per piece.

Compare to actual weight

Weigh each piece on a calibrated scale — the actual gross weight.

Take the greater figureConfirm per-piece vs. per-shipment method with your specific carrier

Chargeable weight per piece is whichever of the two is higher — then sum across all pieces for the shipment total, or confirm your carrier's specific method for mixed shipments.

Industry Standard

6000 is the IATA/TACT standard divisor — not every carrier or mode uses it

Some couriers and domestic services apply a different divisor (5000 is common). Always confirm the specific divisor your quote is based on before comparing rates across carriers or modes.

Source: IATA TACT Rules, volumetric weight standard.

Worked example

A worked example: 2 pieces, mixed density

Take a 2-piece shipment: one carton measuring 60×50×40cm weighing 25kg, and one carton measuring 100×80×60cm weighing 18kg — a genuinely bulky, light second piece.

Piece 1: 60×50×40 = 120,000cm³ ÷ 6000 = 20kg volumetric weight. Actual weight is 25kg, so this piece is charged on actual weight — the denser of the two pieces.

Piece 2: 100×80×60 = 480,000cm³ ÷ 6000 = 80kg volumetric weight. Actual weight is only 18kg — this piece is charged on the much higher volumetric weight of 80kg, not the 18kg the scale shows.

Total chargeable weight for this shipment: 25kg + 80kg = 105kg, even though the combined actual weight is only 43kg. This is exactly the scenario where a shipper is surprised by an invoice that looks much higher than 'what the shipment weighs' — UAL calculates and discloses this before booking, not after the invoice arrives.

What UAL confirms before booking

We calculate chargeable weight per piece against the actual carrier's divisor before quoting, so there's no surprise between the quote and the final invoice.

Transparent chargeable weight calculation at quote stage

Direct carrier rate confirmation, not a marked-up estimate

Frequently asked questions

No — sea freight typically uses a much higher divisor (1000, i.e. 1 cubic metre = 1000kg for volumetric purposes), reflecting the very different economics of ship cargo holds versus aircraft. Don't apply the air freight divisor to a sea freight quote or vice versa.

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Source: IATA TACT Rules, volumetric weight standard (6000 divisor). Last verified July 2026.